XVII.—Embryogenesis and Larval Organs of the Giant Land Snail Achatina fulica Bowdich

1962 ◽  
Vol 68 (3) ◽  
pp. 237-260
Author(s):  
Krishna Chandra Ghose
Keyword(s):  
Digestive Gland ◽  
Posterior Part ◽  
Land Snail ◽  
Mantle Cavity ◽  
Early Embryo ◽  
The Body ◽  
Hind Gut ◽  
Contraction And Relaxation ◽  
Short Time ◽  
Digestive Glands

SynopsisOrganogenesis is completed by 15 days. A modified veliger stage is present. Torsion begins at about the sixth day. The foot rudiment is first to appear. The stomodæum appears as a new structure. The salivary glands develop from the stomodæum by evaginations. The œsophagus is stomodæal, while the crop and the primitive stomach are archenteric in origin. The digestive gland develops as two outgrowths of the primitive stomach. The hind gut is formed by the cells proliferated from the closed posterior end of the archenteron. It opens into the primitive stomach in a 2·5 mm. embryo, and the anus appears very late. The proctodæum is absent. The primordium of the pericardium with the heart, definitive kidney and gonad is mesodermal. The ureter is ectodermal and arises from the mantle cavity by evagination and subsequently communicates with the kidney. Lung and mantle are ectodermal and arise by separate invaginations. The lung fuses with the mantle and loses its separate existence from about a 4 mm. embryo. The nervous system is early to appear and the sense organs, except the statocysts are late in origin. They are ectodermal. The larval organs are: velum, podocyst, larval kidney, nuchal cells and larval digestive gland. The prototroch is the rudiment of the velum. It appears in a very early embryo from the posteroventral part and marks off the anterior border of the stomodæum. The cells of the prototroch become hyaline, vacuolate and develop cilia in a 2·25 mm. embryo, and it is transformed into velum. The velum helps in driving albumen into the larval and adult digestive glands and is resorbed in the body-wall epithelium. The rudiment of the foot first appears after the completion of gastrulation, and the podocyst is differentiated from it later. It steadily increases in size, assumes a hood-like shape, exhibits contraction and relaxation movements and begins to reduce when the embryo attains 3·25 mm. size. It is completely resorbed in the foot. The larval kidneys are mesodermal in origin, appear, in a 920 μ embryo. They begin to degenerate after the formation of the functional definitive kidney and disappear in a late larva. The kidneys are U-shaped, the cells of the closed anterior and bear pseudopodia, which are almost totally replaced by cilia afterwards. The kidney opens to the exterior posteriorly. The cells become vacuolated and excretory granules accumulate in the vacuoles. The nuchal cells first appear in a 2·5 mm. embryo and are excretory. They increase both in number and size with the growth of the embryo and persist throughout the larval period. The endoderm cells of the major portion of the archenteron except a small posterior part, enlarge in size, develop vacuoles and form a larval digestive organ for the purpose of digestion of albumen. Even after the formation of the adult digestive gland, the larval digestive gland functions for a short time, then degenerates and disappears at the end of the larval life.

XIV.—Origin and Development of the Digestive System of the Giant Land Snail Achatina fulica Bowdich

1962 ◽  
Vol 68 (3) ◽  
pp. 186-207 ◽  
Author(s):  
Krishna Chandra Ghose
Keyword(s):  
Anterior Chamber ◽  
Digestive Gland ◽  
Digestive System ◽  
Anterior Part ◽  
Posterior Part ◽  
Land Snail ◽  
Posterior Chamber ◽  
Achatina Fulica ◽  
Hind Gut ◽  
Late Embryo

SynopsisThe stomodæum appears as an ectodermal invagination. The oesophagus develops from an outgrowth (posterior) and the radular sac from a ventral evagination of the floor of the stomodæum. The basal epithelium of the radular sac secretes the radular membrane and the teeth, while the dorsal epithelium contributes towards the hardening of the teeth. The subradular cavity is formed from a depression of the floor and the salivary glands from two evaginations of the roof of the stomodæum. The buccal cartilage is mesodermal, while the jaw is ectodermal. The blastopore closes. Only the posterior part of the archenteron takes part in the formation of the gut, from which the crop, stomach and the digestive gland develop. The anterior chamber of the crop develops from a diverticulum of the archenteron. The anterior and posterior lobes of the digestive gland arise from the anterior part of the primitive stomach dorsally and on the left side respectively; the posterior chamber of the crop from the anteroventral region of the primitive stomach, and the stomach from the posterior right side of its floor. The hind gut appears by the arrangement of cells proliferated from that part of the archenteron where blastopore closes. It opens anterodorsally into the primitive stomach in a 2½ mm. embryo; the anus appears in a late embryo about 12 days old.

On the Life History and the Anatomy of the Early Stages of Forcipomyia (Diptera, Nemat., Ceratopogoninae)

Parasitology ◽  
1924 ◽  
Vol 16 (2) ◽  
pp. 164-213 ◽  
Author(s):  
Leslie G. Saunders
Keyword(s):  
Abdominal Segment ◽  
Posterior Extremity ◽  
Posterior Part ◽  
The Body ◽  
Malpighian Tubules ◽  
Close Relative ◽  
Full Detail ◽  
Dorsal Vessel ◽  
Tracheal System ◽  
Hind Gut

(1) Forcipomyia is one of the few genera of the Ceratopogoninae (Chironomidae) whose larvae are not aquatic. They retain, however, the apneustic condition typical of the entire family, and are therefore compelled to live in moist places such as beneath the rotting bark of fallen trees, in the hollow tap roots of dead plants, in wounds and rot holes in trees, in drying horse and cow manure, in decaying fungi, and in the nests of ants. The immature forms are strongly gregarious.(2) The larvae pass through four stages, each lasting about a week; the successive changes in chaetotaxy at each moult is recorded in the discussion of F. picea. All known European species of this genus hibernate as third or fourth stage larvae. The duration of the pupal stage is about one week; the length of life of the adult has not been determined. There are usually three generations per annum. The adults are known to suck the blood of other insects.(3) The larvae are eucephalous, more or less cylindrical, 3–6 mm. long, with eleven clearly denned segments (three thoracic and eight abdominal, the eighth divided into two apparent segments). Progression is achieved by means of a retractable, biramous, prothoracic pseudopod, and a ventral hook-studded ridge on the ultimate abdominal segment, with the occasional aid of the mandibles.(4) The head and body bear numerous lanceolate and simple hairs of great specific importance.(5) The mouth-parts consist of a fleshy labrum, a pair of small premandibles, a pair of long, slender mandibles working in the sagittal plane on either side of the labrum, a pair of reduced maxillae of fleshy nature with chitinous internal supports, and a simple untoothed labium. Within the head there is a complicated chitinous structure, the hypopharynx; this is figured and described in full detail and its action in comminuting the food is revealed for the first time.(6) No investigation has hitherto been made of the internal anatomy. The alimentary canal, consisting of buccal cavity, hypopharynx, oesophagus, mid-gut, and hind-gut, is quite simple in structure, without nodules or caecal chambers. It is only slightly longer than the body, a loop occurring in the hind-gut when the larva contracts.(7) The malpighian tubules are either two or three in number, the latter condition being unique among insects. The third is ventral, passing into the posterior part of the body only.(8) The salivary glands are a pair of S-shaped bodies closely adhering to the walls of the anterior portion of the mid-gut; they are chiefly composed of large binucleate cells.(9) The circulatory system consists of a dorsal vessel extending throughout the body and passing between the lobes of the brain above the oesophagus into the head. In the eighth abdominal segment it enlarges slightly to form the heart, with one pair of ostia or valves situated on its posterior extremity.(10) The nephrocytes are arranged segmentally, four to each abdominal segment and a single mass in the thorax, all attached to the dorsal vessel. The excretory function of these cells was demonstrated by injection of ammonia-carmine into the body cavity.(11) The nervous system is only very slightly cephalised, there being seven ganglia for the eight abdominal segments and three in the thorax; the normal bilobed brain is situated in the thorax in all larval stages. The sympathetic system is described, and differs somewhat from that of its close relative, Chironomus.(12) Despite the absence of spiracles there is a well-developed tracheal system in the form of two main trunks with transverse connections, branch tracheae, and subcutaneous plexuses.(13) The muscular system, oenocytes, fat-body, and gonads have also been studied in detail.(14) The larval skin is retained upon the last four or five abdominal segments of the pupa.(15) The characters used for determining the species, in their order of importance, are as follows: Larva: chaetotaxy, prothoracic pseudopod, markings of the head, anal blood-gills. Pupa: cuticular spines, prothoracic horns.(16) The larvae and pupae of nine species of Forcipomyia are described with particular reference to their specific characters. Descriptions of the adults of two new species, F. radidcola and F. pulchrithorax, by Mr F. W. Edwards, are appended.(17) Closely related forms are Euforcipomyia and other exotic subgenera not yet named, and the genus Atrichopogon (now including Kempia). Dasyhelea belongs to this group of hairy-winged flies, but its larvae partly resemble those of the bare-winged Ceratopogonines in that they have lost the pro-thoracic pseudopod and macrochaetae, but retain the anal hooks.

The Circulatory Physiology of Helix Pomatia

1973 ◽  
Vol 59 (2) ◽  
pp. 275-282
Author(s):  
BARBARA A. SOMMERVILLE
Keyword(s):  
Anterior Part ◽  
Pulmonary Veins ◽  
Helix Pomatia ◽  
Mantle Cavity ◽  
Heart Beat ◽  
The Body ◽  
Semilunar Valve ◽  
Breathing Cycle ◽  
Pericardial Cavity ◽  
Contraction And Relaxation

1. Helix uses the muscular floor of the mantle cavity to effect several movements. The contraction and relaxation of these muscles is concerned primarily with filling the lung and absorption of oxygen under pressure. The movement is linked with that of the pneumostome, which is open while the floor is depressed and closed when it is raised. An exaggeration of the breathing movements serves to generate the pressure in the cephalopedal haemocoel, which propels the anterior part of the body out of the shell. 2. The rate and regularity of heart-beat vary during the breathing cycle, being slow and irregular when the pneumostome is closed and fast and regular when it is open. 3. Observation of the intact heart of Helix showed changes in the degree of filling indicating an increased blood flow from the haemocoel to the pulmonary veins and heart when the mantle cavity floor was depressed. The total volume of the heart and pericardial cavity was greater at ventricular diastole than at ventricular systole. 4. When the cardiac nerve was severed a significant but inconsistent relationship between the heart activity and the breathing cycle remained. 5. Helix pomatia, H. aspersa, Archachatina, Monodonta and Anion ater all have a semilunar valve on the common aorta directed so as to prevent blood flowing from the aorta into the ventricle. H. pomatia and H. aspersa have a second semilunar valve in the anterior aorta while in Archachatina the anterior aorta passes through a muscular constriction.

The internal anatomy of the woodlouse, Metoponorthus pruinosus (Brandt), (Porcellionidae, Peracarida)

1968 ◽  
Vol 46 (3) ◽  
pp. 321-327 ◽  
Author(s):  
M. A. Alikhan
Keyword(s):  
Nervous System ◽  
Digestive System ◽  
Circulatory System ◽  
Reproductive Organs ◽  
The Body ◽  
Internal Anatomy ◽  
Suboesophageal Ganglion ◽  
Digestive Tube ◽  
Thoracic Ganglia ◽  
Digestive Glands

Tbe circulatory system, lying in the mid-dorsal line of the body, consists of an oval heart, the opthalmic artery, and a dorsal abdominal artery.The digestive system comprises a wide, large alimentary tube and two pairs of digestive glands. An oesophagus, a proventriculus, midgut, and a short proctodacum or hindgut form the digestive tube. The digestive glands are very well developed and are beaded in form; each pair lies on either side of the alimentary canal.The reproductive organs are well developed in both sexes: in the male they consist of paired testes and their vas deferentia, and in the female paired bilobed ovaries and oviducts.A cerebral or supraoesophageal ganglion, a suboesophageal ganglion, and seven thoracic ganglia form the nervous system. The supraoesophageal ganglion is united with the suboesophageal ganglion by means of the circumoesophageal commissures, whereas the thoracic ganglia and suboesophageal ganglia are linked with each other by paired connectives.The gills and the tracheae are the organs of respiration. The gills are borne of the bases of the pleopods and are enclosed in the branchial chamber. The tracheae are located on the lateral lobes of the first two pleopods only.

scholarly journals Redescription of Paradiplozoon hemiculteri (Monogenea, Diplozoidae) from the type host Hemiculter leucisculus, with neotype designation

Parasite ◽  
2018 ◽  
Vol 25 ◽  
pp. 4 ◽  
Author(s):  
Dagmar Jirsová ◽  
Xuejuan Ding ◽  
Kristína Civáňová ◽  
Eliška Jirounková ◽  
Jana Ilgová ◽  
...  
Keyword(s):  
Southern China ◽  
Phylogenetic Analyses ◽  
Posterior Part ◽  
Original Description ◽  
Molecular Data ◽  
The Body ◽  
Type Host ◽  
Hemiculter Leucisculus ◽  
Morphological And Molecular Data ◽  
Median Plate

Paradiplozoon hemiculteri (Ling, 1973), a member of the Diplozoidae, parasitizes the gills of Asian fish. Not only is the type material unavailable for this species, the original description was poor and somewhat conflicting, and adequate molecular data were not available. What is more, the available morphological and molecular data are inconsistent and fluctuate significantly. Here, we present a redescription of P. hemiculteri based on morphological and molecular data from new isolates collected from the type host, the sharpbelly Hemiculter leucisculus (Basilewsky, 1855), captured at the neotype locality (Shaoguan, Guangdong Province, southern China); a neotype for P. hemiculteri was designated from this collection. The length and width of the body, buccal suckers, pharynx, attachment clamps, sickle and the central hook handle were all measured and the shape of the anterior and posterior part of the median plate and anterior and posterior joining sclerites accurately documented. Phylogenetic analyses based on the sequences of the second rDNA internal transcribed spacer (ITS2) indicated that all new samples clustered together and differed clearly from sequences attributed to P. hemiculteri, which are deposited in GenBank. Our results confirm that P. hemiculteri is the only diplozoid that has demonstrably been found on the gills of H. leucisculus to date.

Developmental stages in the Digenea

Parasitology ◽  
1964 ◽  
Vol 54 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Elon E. Byrd ◽  
William P. Maples
Keyword(s):  
Body Wall ◽  
Developmental Stages ◽  
Snail Host ◽  
The Body ◽  
Body Movements ◽  
Hatching Enzyme ◽  
Apical Papilla ◽  
Short Time ◽  
Membranous Body ◽  
Egg Capsule

The naturally oviposited egg of Dasymetra conferta is fully embryonated and it hatches only after it is ingested by the snail host, Physa spp.Hatching appears to be in response to some stimulus supplied by the living snail. The stimulus causes the larva to exercise a characteristic series of body movements and to liberate a granular sustance (hatching enzyme) from the larger pair of its cephalic glands. This enzyme reacts with the vitelline fluid to create pressure within the egg capsule, and with the cementum of the operculum, so that it may be lifted away. The larva's escape from the shell, therefore, is due to a combination of pressure and body movements.The hatched larva has a membranous body wall, supporting six epidermal plates, an apical papilla, two penetration glands and a central matrix (the presumptive brood mass).It lives for about an hour within the snail and during this time there is a reorganization of the central matrix which terminates in the formation of an 8-nucleated syncytial brood mass.The miracidial ‘case’, consisting of the body wall and the epidermal plates, ultimately ruptures to liberate the brood mass. Once the brood mass is free it penetrates through the gut wall in an incredibly short time.

Isolation of myosalvarsan'a

1930 ◽  
Vol 26 (9) ◽  
pp. 942-942
Author(s):  
H. Bauer
Keyword(s):  
Maximum Amount ◽  
The Body ◽  
Drug Excretion ◽  
Clinical Observations ◽  
Short Time ◽  
Detailed Technique ◽  
Cessation Of Treatment

Abstracts. Venereology and Dermatology. Hugo Bauer (D. Z. Bd. 57, H. 4, 29), aiming to study the secretion of myosalvarsan'a, took under observation 4 syphilitics treated with injections of the drug. Excretion of myosalvarsan'a, as well as its absorption, is similar to 'neo' and sulfoxylsalvarsan'y. Most of the arsenobenzol'a introduced into the body is released within a "short time" after injection; four weeks after the cessation of treatment, the body is freed from the maximum amount of introduced As. The author believes that the clinical observations, on the basis of which it is argued that if certain intervals are observed between courses, the cumulative action of As does not occur, are completely fair. The author gives a detailed technique for determining As in selections and supplies the article with visual tables and curves of his own observations.

scholarly journals Necrotizing fasciitis with group A Streptococci and Eggerthella lenta as a complication of Varicella in a child – case presentation –

2014 ◽  
Vol 20 (1) ◽  
pp. 35-39
Author(s):  
Cambrea Simona Claudia ◽  
Ilie Maria Margareta ◽  
Carp Dalia Sorina ◽  
Ionescu C.
Keyword(s):  
Necrotizing Fasciitis ◽  
Severe Disease ◽  
The Body ◽  
Group A Streptococci ◽  
Threatening Condition ◽  
Life Threatening ◽  
Group A ◽  
The Right ◽  
Surgery Department ◽  
Short Time

ABSTRACT Necrotizing fasciitis is a life threatening condition that can be quickly spread through the flesh surrounding the muscle. The disease can be polymicrobial, or caused by group A beta hemolytic Streptococci, or by Clostridium spp. We present a case of a 7 years old girl, which was hospitalized in Children Infectious Diseases Department in a 7th day of chickenpox (hematic crusts all over the body), high fever, asthenia, vomiting, oligoanuria, and tumefaction, pain and functio lessa in the right thigh. In a very short time in the right thigh swelling, edema and congestion have increased gradually, and in the third highest middle thigh the ecchymotic areas appeared evolving towards bubbles and blisters which included the right thigh and calf. After excluding the diagnosis of thrombophlebitis was raised suspicion of necrotizing fasciitis. CT pelvic scan evidenced pelvic asymmetry by maximus and medium right gluteal muscles swelling with important inflammatory infiltrate extended laterally in the subcutaneous adipose tissue. In blood culture was isolated Eggerthella lenta, and from throat swab was isolated group A Streptococci. Treatment consists of a combination of antibiotics associated with intravenous immunoglobulin administration. Despite medical treatment evolution worsened and required transfer in a pediatric surgery department where emergent surgical debridement associated with intensive antibiotic therapy was done. After this intervention evolution was slowly favorable without major limb dysfunction. Polymicrobial necrotizing fasciitis is a severe disease, which if recognized early can have a favorable outcome.

scholarly journals Treatment of cattle pyroplasmidosis in the conditions of Dagestan Republic

2021 ◽  
Vol 344 (5) ◽  
pp. 8-10
Author(s):  
S. Sh. Abdulmagomedov ◽  
A. Yu. Aliev ◽  
R. M. Bakrieva ◽  
E. A. Belkin
Keyword(s):  
Live Weight ◽  
The Body ◽  
Control Measures ◽  
Ixodid Ticks ◽  
Farm Animals ◽  
Blood Parasites ◽  
Control Group ◽  
Single Intramuscular Injection ◽  
Short Time ◽  
And Control

Relevance. Dagestan Republic in terms of natural and climatic characteristics is the most favorable for the of ixodid ticks - carriers of pathogens of blood-parasitic diseases of farm animals. In this regard, further improvement of the set of scientifically grounded control measures and the search for new promising chemotherapeutic drugs of the prevention and treatment of pyroplasmidosis of cattle are major problem of great national economic importance.Materials and methods. The studies were carried out in farms, unfavorable on pyroplasmidosis, in the conditions of Dagestan Republic. The object of the study was cattle, spontaneously invaded by various types of blood parasites. Experеmental and control groups in production experiments were selected according to the principle of analogues. In the first control group (n = 10) the drug was not used. The second (n = 10) was injected with the drug DAC 5% at a dose of 1 ml/20 kg (DV 2.5 mg/kg), intramuscularly, at the rate 5 ml per 100 kg of live weight. The animals of the third (n = 10) were injected with the injectable preparation forticarb 10% at a dose of 4 ml/100 kg (DV 4 mg/kg) of live weight, intramuscularly, once.Results. It was found that with a single intramuscular injection of forticarb at the rate 2 ml/50 kg of live weight, the temperature and parasitic reaction in the body of sick animals decreased in a very short time. Therapeutic efficacy in pyroplasmidosis of cattle was 90%.

scholarly journals Opposite asymmetries of face and trunk and of kissing and hugging, as predicted by the axial twist hypothesis

2019 ◽  
Author(s):  
Marc HE de Lussanet
Keyword(s):  
Bilateral Symmetry ◽  
Optic Chiasm ◽  
Early Embryo ◽  
The Body ◽  
Head Region ◽  
Evolutionary Selection ◽  
Left Handed ◽  
Secondary Feature ◽  
Half Turn ◽  
Axial Twist

The contralateral organization of the forebrain and the crossing of the optic nerves in the optic chiasm represent a long-standing conundrum. According to the Axial Twist Hypothesis (ATH) the rostral head and the rest of the body are twisted with respect to each other to form a left-handed half turn. This twist is the result, mainly, of asymmetric, twisted growth in the early embryo. Evolutionary selection tends to restore bilateral symmetry. Since selective pressure will decrease as the organism approaches symmetry, we expected a small control error in the form of a small, residual right-handed twist. We found that the mouth-eyes-nose (rostral head) region shows a left-offset with respect to the ears (posterior head) by up to 0.8° (P<0.01, Bonferroni-corrected). Moreover, this systematic aurofacial asymmetry was larger in young children (on average up to 3°) and reduced with age. Finally, we predicted and found a right-sided bias for hugging (78%) and a left-sided bias for kissing (69%). Thus, all predictions were confirmed by the data. These results are all in support of the ATH, whereas the pattern of results is not explained by existing alternative theories. As of the present results, the ATH is the first theory for the contralateral forebrain and the optic chiasm whose predictions have been tested empirically. We conclude that humans (and all other vertebrates) are fundamentally asymmetric, both in their anatomy and their behavior. This supports the thesis that the approximate bilateral symmetry of vertebrates is a secondary feature, despite their being bilaterians.

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