Memoirs: The Reproductive System and Associated Organs of the Brittle-Star Ophiothrix Fragilis

1940 ◽  
Vol s2-82 (326) ◽  
pp. 267-309
Author(s):  
J. B. SMITH
Keyword(s):  
Breeding Season ◽  
Reproductive System ◽  
Body Wall ◽  
The Body ◽  
The Other ◽  
Larval Life ◽  
Free Swimming ◽  
Axial Organ ◽  
The Right ◽  
Stone Canal

1. The organs associated, either directly or indirectly, with reproduction in the Ophiuroidea are the axial organ and related sinuses (axial organ complex), the genital raehis, the gonads (localized expansions of the raehis), the gonoducts, and the genital bursae. 2. Evidence is presented in favour of the view of Fedotov (1924) that the axial organ of Ophiuroids is made up of two closely associated parts each surrounded by its own sinus from the wall of which it is, during development, proliferated. The left axial sinus (aboral in the adult) is derived from the left anterior coelom of the larva, the right axial sinus (oral in the adult) from the madreporie vesicle which itself is a derivative of the right anterior coelom of the larva. 3. The ampulla of the stone canal is continuous with, and is part of, the left axial sinus. 4. An account is given of the morphology and histology of the genital rachis and sinus. 5. Examination of the gonads of female Ophiothrix indicate that the breeding season extends from about March to October and that, during this time, there is periodic emission of ova, probably at monthly intervals. Males, on the other hand, produce sperm all the year round. 6. The genital bursae number two pairs to each interradial pouch. They serve, primarily, as organs of respiration. Special mechanisms, which are described, are concerned in the intake and expulsion of water. 7. The gonads do not discharge their products directly into the genital bursae nor through temporarily formed pores in the body-wall but through specially developed and permanent gonoducts, one to each of the ten gonads. 8. Young specimens found in the genital bursae have attained their position only after a period of free-swimming larval life. After settling and metamorphosing, some of the young individuals crawl into the bursae. 9. As a consequence of the previous observation it is pointed out that the presence of the young within the genital bursae of the adult is by no means an indication of a viviparous habit.

Mediolateral somitic origin of ribs and dermis determined by quail-chick chimeras

Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4611-4617 ◽  
Author(s):  
I. Olivera-Martinez ◽  
M. Coltey ◽  
D. Dhouailly ◽  
O. Pourquie
Keyword(s):  
Skeletal Muscles ◽  
Body Wall ◽  
Primitive Streak ◽  
Axial Skeleton ◽  
Lateral Compartment ◽  
The Body ◽  
The Other ◽  
Lateral Part ◽  
Respective Contribution ◽  
Epaxial Muscles

Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment.

A new genus and species of Sclerodactylidae (Echinodermata: Holothuroidea: Sclerothyoninae) from the Pacific coast of Panama, and assignment of Neopentamera anexigua to Sclerothyoninae

Zootaxa ◽  
2018 ◽  
Vol 4429 (1) ◽  
pp. 157
Author(s):  
LUCIANA MARTINS ◽  
MARCOS TAVARES
Keyword(s):  
Body Wall ◽  
New Genus ◽  
Pacific Coast ◽  
The Body ◽  
The Other ◽  
Monotypic Genus ◽  
New Genus And Species ◽  
The Pacific ◽  
Calcareous Ring

Paulayellus gustavi, a new sclerodactylid genus and species, is described from the Pacific coast of Panama. The new genus and species is assigned to the subfamily Sclerothyoninae based on a suite of characters, which include the radial and interradial plates of the calcareous ring united at the base only. Paulayellus gen. nov. differs from the other Sclerothyoninae genera in having posterior processesof radial plates undivided. Additionally, differs from Sclerothyone, Thandarum and Neopentamera in having knobbed buttons, plates and cups in the body wall (whereas the body wall is furnished only with tables and plates in Sclerothyone, Temparena and Thandarum, and only with knobbed buttons and plates in Neopentamera). The new genus is, so far, monotypic. The also monotypic genus Neopentamera proved to have the radial and the interradial plates of the calcareous ring united at the base only, as typically found in the Sclerothyoninae, and is therefore transferred to that subfamily. The discovery of a new genus in the Sclerothyoninae and the transfer of Neopentamera required the amendation of the diagnosis for the subfamily. A key to the Sclerothyoninae is given. 

Memoirs: On the Reproductive Processes of the Earthworm, Lumbricus Terrestris

1925 ◽  
Vol s2-69 (274) ◽  
pp. 245-290
Author(s):  
A. J. GROVE
Keyword(s):  
Body Wall ◽  
Seminal Fluid ◽  
Lumbricus Terrestris ◽  
The Body ◽  
The Other ◽  
Reproductive Processes ◽  
Longitudinal Muscles ◽  
Earthworm Lumbricus

During the sexual congress of L.terrestris, the co-operating worms become attached to one another in a head-to-tail position in such a way that segments 9-11 of one are opposed to the clitellum of the other, and vice versa. At these points the attachment between the worms is an intimate one, assisted by the secretion of the glands associated with the diverticula of the setal pores found in certain segments, and is reinforced by the mutual penetration of the setae into the opposed body-surfaces. There is also a slighter attachment between segment 26 of one and 15 of the other. Each worm is enclosed in a slime-tube composed of mucus secreted from the epidermis. The exchange of seminal fluid is a mutual one. The fluid issues from the apertures of the vasa deferentia in segment 15, and is conducted beneath the slime-tube in pit-like depressions in the seminal grooves, which extend from segment 15 to the clitellum on each side of the body, to the clitellum, where it accumulates in the space between the lateral surfaces of segments 9-11 of one worm and the clitellum of the other. Eventually it becomes aggregated into masses in the groove between segments 9 and 10, and 10 and 11, and passes thence into the spermathecae. The seminal groove and its pit-like depressions are brought into existence by special muscles lying in the lateral blocks of longitudinal muscles of the body-wall.

Mechanoreceptors, Photoreceptors and Rapid Conduction Pathways in the Leech, Hirudo Medicinalis

1969 ◽  
Vol 50 (1) ◽  
pp. 129-140 ◽  
Author(s):  
M. S. LAVERACK
Keyword(s):  
Nerve Cord ◽  
Body Wall ◽  
The Body ◽  
Nerve Fibres ◽  
Peripheral Stimulation ◽  
Conducting Pathway ◽  
Transmission Of Information ◽  
Rapid Transmission ◽  
The Right ◽  
Light Flashes

1. Mechanoreceptors in the body wall of the leech Hirudo are stimulated by deformation of the animal's surface. They respond at all frequencies of stimulation up to about 50-60 Hz. 2. Light flashes, from a microscope lamp or an electronic flash source, are also a potent means of peripheral stimulation. 3. After peripheral stimulation impulses can be recorded in a fast central pathway. This pathway conducts equally well in the posterior to anterior and in the opposite directions. 4. Interference with either the right or left connective linking any two segmental ganglia does not interrupt the rapid conduction of these impulses. 5. Severance of the median connective or Faivre's nerve interrupts conduction. This seems to implicate at least one, and possibly more, of the nerve fibres of this median connective in the rapid transmission of information from the extremities of the body. 6. A slower conducting pathway also exists in the nerve cord.

An Account of Larval Budding in the Compound Ascidian, Hypsistozoa fasmeriana

1959 ◽  
Vol s3-100 (52) ◽  
pp. 575-589
Author(s):  
BERYL I. BREWIN
Keyword(s):  
Neural Tube ◽  
Ventral Side ◽  
The Other ◽  
Free Swimming ◽  
Close Link ◽  
Bud Formation ◽  
Maximal Size ◽  
The Right ◽  
Sexually Mature ◽  
Posterior Position

Larval budding in Hypsistozoa fasmeriana is in many ways unique in the sub-family Holozoinae. The stolon, which projects from the left side of the oozooid, is large (235 µ in diameter, 1.8 mm in length) and reaches maximal size before severance of buds occurs. The buds arise one at a time and 9 to 14 are formed. Test forms rapidly between a newly severed bud and the remainder of the stolon. Thus the buds are moved along an arc of a spiral which runs from the left side of the oozooid somewhat anteriorly across the ventral side and posteriorly up the right side. By the end of bud formation the first-formed bud occupies the most posterior position, lying high up on the right side of the oozooid. Each larval bud develops directly into a blastozooid and by the time the tadpole becomes free-swimming there is a considerable degree of organogenesis. The blastozooids together with the oozooid form a ring of zooids tilted slightly away from the vertical. After metamorphosis of the tadpole this ring becomes horizontal, but the tilt is still maintained with the oozooid occupying the most elevated position. Thus in the young colonies the plane of the head is slightly off the horizontal--an arrangement which persists throughout the life of the colony. The development of larval buds in this ascidian is not delayed until after dedifferentiation of the oozooid, as is the case in the other Holozoinae. The blastozooids function simultaneously with the oozooid. They do not, however, become sexually mature, being presumably of sub-maximal size for the species. The newly severed bud differs from that of other Holozoinae in having an extensive epicardial tube and a thick mesenchymal layer of densely granulated cells. The epicardium of the blastozooid is formed from the posterior end of the original epicardial tube. It remains single. The neural tube arises from the left peribranchial sac. H. fasmeriana forms a close link between the sub-family Holozoinae and the sub-family Polyclininae. It resembles the Holozoinae in form of gut, position and mode of origin of the brood pouch, and position of the cardio-pericardium. It shares with the Polyclininae the post-abdominal position of the gonads as well as the structure and organogenesis of the buds.

scholarly journals XIV.—Ancient Gold Ornaments: described by John Yonge Akerman, Esq. Secretary

Archaeologia ◽  
1853 ◽  
Vol 35 (1) ◽  
pp. 190-193
Author(s):  
John Yonge Akerman
Keyword(s):  
Light Chain ◽  
The Body ◽  
The Other ◽  
Asia Minor ◽  
Plate Viii ◽  
Left Hand ◽  
Small Loop ◽  
The Individual ◽  
The Right ◽  
Of Greece

With the exception of Figs. 1, 2, 3, the Gold Ornaments engraved in Plate VIII. have no reference whatever to each other. The first three were obtained by Viscount Strangford, Director of the Society, from a Greek priest at Milo, in the year 1820. Figs. 1 and 3 appear to have formed the ends of a light chain, and the other (fig. 2) to have been pendent by a small loop on the top of the head. The figure has unfortunately lost the feet and the left hand, but the other parts are perfect. The right hand is raised in an admonitory attitude. The forehead appears as if encircled with a wreath, while the body is crossed by what would seem to be intended for the tendril of a vine. The necklace was formerly in the collection of the late Mr. H. P. Borrell, of Smyrna, but I am informed by his brother, Mr. Maximilian Borrell, who now possesses it, that no record exists of its discovery, and that he cannot learn the name of the individual from whom it was purchased. It was well known that Mr. H. P. Borrell was in the habit of purchasing ancient coins, which were sent to him from all parts of Greece and Asia-Minor, and that many rare and unique specimens fell into his hands, of which he contributed descriptions in various volumes of the Numismatic Chronicle. The necklace may, therefore, have been included in one of these numerous consignments, and we can scarcely indulge the hope that the place of its discovery will ever be made known. As an example of ancient art, it may vie with the most elaborate and beautiful specimens of goldsmiths' work of any age or period. The details are wonderfully minute and delicate, even the backs of the button-like objects at the ends of the pendent cords being elaborately finished.

scholarly journals Cervico-pectoral Ectopia Cordis in Two Holstein Calves

1993 ◽  
Vol 30 (6) ◽  
pp. 529-534 ◽  
Author(s):  
T. Hiraga ◽  
M. Abe ◽  
K. Iwasa ◽  
K. Takehana ◽  
A. Tanigaki
Keyword(s):  
Body Wall ◽  
Vena Cava ◽  
The Body ◽  
The Other ◽  
Urogenital System ◽  
Ectopia Cordis ◽  
Thoracic Inlet ◽  
Holstein Calves ◽  
Common Pathogenesis ◽  
Fetal Stage

Two Holstein calves affected with cervico-pectoral ectopia cordis, a male (No. 1) delivered stillborn and a female (No. 2) died 1 hour after birth, were examined macroscopically and radiographically to assess the severity and elucidate the teratogenesis of the anomaly. The heart of one calf was covered by the intact pericardium and skin and displaced to the caudalmost portion of the ventrocervical region, just cranial to an enlarged thoracic inlet. The cranial vena cava and the vena azygos were duplicated. The sternum was bilaterally divided into two parts fused only at the xyphoid process and was semicircular. The heart of the other calf, covered solely by the pericardium, was exposed ventrally from an oval opening in the body wall just cranial to a defective Y-shaped sternum. In both calves, the arterial branching pattern from the aortic arch was intermediate between the patterns of the dog and pig, and in each case a single pulmonary vein emptied into the left atrium. Pronounced or slight torticollis, cleft palate, and abnormalities in the urogenital system were also found. From an embryological perspective, cervical and pectoral ectopia cordis have a common pathogenesis; the cervical type occurs at a slightly earlier fetal stage than the pectoral type.

Barrier and Penetration Scores in Relation to Some Objective and Subjective Somesthetic Measures

1984 ◽  
Vol 59 (1) ◽  
pp. 195-202 ◽  
Author(s):  
Nicoletta Sabatini ◽  
Vezio Ruggieri ◽  
Maria Milizia
Keyword(s):  
The Body ◽  
The Other ◽  
Inverse Relation ◽  
Direct Relation ◽  
Body Perception ◽  
Muscular Tone ◽  
The Right ◽  
Different Characteristics ◽  
Female Subjects

Barrier and Penetration scores in relation to some variables, such as muscular tone at rest, sensitivity to tickle, and body perception were studied in a group of 35 female subjects. While no correlations appear within the whole group of subjects between Barrier scores and the other variables, an inverse relation emerges between Penetration scores and muscular tone on the left side of the body. Dividing subjects on the basis of Barrier scores, three groups with different characteristics appear: 12 subjects with high Barrier scores show an inverse relation of Barrier scores with sensitivity to tickle on the right side of the body; 12 subjects with middle Barrier scores show a direct relation of Barrier scores with muscular tone and an inverse one with both latency of tickle on the right half of the body and body perception; 11 subjects with low Barrier scores show an inverse relation of Barrier scores with durations of tickle on both sides of the body.

Tactile Recognition of Mirror Images by Children: Intermanual Transfer and Rotation of the Palm

Perception ◽  
1988 ◽  
Vol 17 (4) ◽  
pp. 535-547
Author(s):  
Barbara Heath ◽  
George Ettlinger ◽  
Josephine V Brown
Keyword(s):  
Memory Trace ◽  
Stimulus Presentation ◽  
The Body ◽  
The Other ◽  
Intermanual Transfer ◽  
The Right ◽  
Recognition Errors ◽  
Hand Recognition ◽  
Stimulus Materials ◽  
Other Orientation

In order to evaluate the importance of the axis of stimulus presentation, inter- and intramanual recognition of mirror pairs was studied with the stimulus materials aligned along the front/back axis (whereas in previous work the mirror pairs were aligned along the left/right axis). Children were allowed to feel shapes with the whole hand, with only four fingers (excluding the thumb), or with only the index finger. After learning with one hand, recognition was tested in experiment 1 with the other hand; after learning with one orientation of the hand (palm down or up), recognition was tested in experiment 2 with the other orientation (palm up or down) of the same hand; after learning with one coronal alignment of the hand (to the left or right), recognition was tested in experiment 3 with the other alignment (to the right or left), but without rotation, of the same hand. Significantly fewer intermanual recognition errors were made on mirror pairs with the materials oriented along the front/back axis than in previous work when oriented along the left/right axis. This supports the suggestion that such errors arise when the stimuli are oriented along the left/right axis during formation of the memory trace. The same trend was unexpectedly obtained for intramanual recognition errors (after rotation of the hand). These errors (after hand rotation) are largely due to coding with respect to the hand; they are reduced when the hand is not aligned with the body axis, since then coding can also occur in relation to the environment.

scholarly journals Existence of mandibular directional asymmetry in the European wild boar (Sus scrofa Linnaeus, 1758)

2014 ◽  
Vol 31 (04) ◽  
pp. 228-232
Author(s):  
P. Parés-Casanova
Keyword(s):  
Sus Scrofa ◽  
Age Groups ◽  
The Body ◽  
The Other ◽  
Directional Asymmetry ◽  
Asymmetric Structure ◽  
Dorsal Aspect ◽  
European Wild Boar ◽  
Perfect Symmetry ◽  
The Right

Abstract Introduction and material and methods. We studied a sample of 37 dentulous dry mandibles from European wild board (Sus scrofa) and compared both the right and left sides in their dorsal aspect. To study the influence of age, the samples were grouped according to dental status: “subadults” (erupting 3rd M, n=22) and “adults” (fully erupted 3rd M, n=15). Individual levels of asymmetry were analysed from x- and y-coordinates of the 16 landmarks on the dorsal aspect of the mandible. Results. The analysis separated directional asymmetry (one side of the body with a larger character value than the other) and fluctuating asymmetry (small random deviations from perfect symmetry), which were both found to be significant. Conclusion. The condylar ramus was the most asymmetric structure for both age groups.

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