Memoirs: On the Reproductive Processes of Earthworms: Part I. The Process of Copulation and Exchange of Sperms in Eutyphoeus waltoni Mich

1927 ◽  
Vol s2-71 (283) ◽  
pp. 479-502
Author(s):  
KARM NARAYAN BAHL
Keyword(s):  
Nutrient Medium ◽  
Seminal Fluid ◽  
The Other ◽  
Spermathecal Duct ◽  
Prostatic Fluid ◽  
Reproductive Processes ◽  
First Time ◽  
Male Genital

1. The method of exchange of the seminal fluid in Eutyphoeus is very simple and direct as compared with the elaborate process in Lumbricus. No intermediate structures like the clitellum and temporary seminal grooves take part in the process in Eutyphoeus. 2. During sexual congress, the co-operating worms become attached to one another in a head-to-tail position in such a way that the spermathecal apertures (7/8) of one are apposed to the penial segment (seventeenth) of the other and vice versa. 3. The male ‘genital pits’ are everted to form ‘genital cups’ and the penis is protruded. The genital cups produce a suction on the area of skin surrounding the spermathecal pores of the co-operating worm, and thus cause the formation of spermathecal papillae. In this way a ‘peg and socket’ joint is formed at four places in a copulating pair and, at each joint, the attachment is intimate, the genital cup closely embracing the spermathecal papilla and the penis penetrating the spermathecal duct. 4. There is a further attachment between the ventral surfaces of the two worms by means of permanent copulating papillae and temporary integumentary outgrowths. 5. The function of the penis as an intromittent organ in Eutyphoeus has been elucidated for the first time and a distinction has been made between ‘functional’ and ‘reserve’ penial setae. 6. The exchange of sperms is mutual. The penes inject both spermatic and prostatic fluids into the spermathecae. The sperms are invariably found in the diverticula and not in the ampulla, which probably contains a secretion of its own epithelium. There is some evidence to believe that the prostatic fluid serves a nutrient medium for the sperms in the seminal chambers of the diverticula.

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.

scholarly journals Memoirs: On the Reproductive Processes of the Brandling Worm, Eisenia Foetida. (Sav.)

1926 ◽  
Vol s2-70 (280) ◽  
pp. 559-581
Author(s):  
A. J. GROVE ◽  
L. F. COWLEY
Keyword(s):  
Seminal Fluid ◽  
Ventral Side ◽  
The Other ◽  
Eisenia Foetida ◽  
Fourth Segment ◽  
Oval Form ◽  
Reproductive Processes ◽  
Free Edges

During coition in E. foetida the worms come together in such a way that the clitellum of one embraces segments 8-11 of the other. The whole of the clitellar and interclitellar regions are enclosed in a protective coition slime-tube in which are developed constricting bands at both ends of the clitella. The line of the seminal groove extends from the fifteenth segment to near the posterior end of the clitellum. The seminal fluid travels backwards, beneath the slime-tube, in pit-like depressions of the epidermis, which, on reaching the end of the line of the seminal groove, travel to the ventral side of the clitellum, depositing the sperm between its free edges and the adposed segments. The pit-like depressions appear and travel backwards at the rate of about ten per minute on each side of each worm, making four streams of seminal fluid in all. The sperm-masses are brought over the dorsally placed apertures of the spermathecae by the embracing and releasing, movements of the clitellum. The almost complete embracing of the adposed segments by theclitellum is facilitated by the infolding of the ventral surfaces of these segments. It has been determined that cocoon deposition is a separate process from that of coition. This disposes of Foot's (1898) statement that cocoon formation takes place while the worms are still united, which probably arose from the failure to distinguish between the coition slime-tube and the cocoon slime-tube, and the mistaking of the constricting bands evident during coition for the ends of the cocoons. During cocoon formation the slime-tube is developed, extending from about the seventh to about the thirty-fourth segment. The cocoon membrane is then secreted around the clitellum, which assumes an oval form with a marked constriction posteriorly and a lesser one anteriorly. Whilst the cocoon still surrounds the clitellum the eggs are passed back into it. It is still uncertain, however, whether the spermatozoa similarly pass back into the cocoon or are squeezed into it from the spermathecae during its passage over their apertures. The deposition of the cocoon is effected by the gradual withdrawal of the worm with the exception of the anterior three or four segments, during the freeing of which there usually occur three or four characteristic jerks.

Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

2012 ◽  
Vol 39 (2) ◽  
pp. 217-233 ◽  
Author(s):  
J. David Archibald
Keyword(s):  
Fossil Record ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Charles Darwin ◽  
The Other ◽  
Charles Lyell ◽  
Single Origin ◽  
Molecular Studies ◽  
Richard Owen ◽  
First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

Sphagnum mosses (Sphagnaceae, Bryophyta) of mires Chefandzar and Masota in North Ossetia (Caucasus)

2018 ◽  
Vol 52 (2) ◽  
pp. 455-462 ◽  
Author(s):  
G. Ya. Doroshina ◽  
I. A. Nikolajev
Keyword(s):  
Plant Communities ◽  
The Other ◽  
North Caucasus ◽  
Sphagnum Mosses ◽  
Greater Caucasus ◽  
The North ◽  
First Time ◽  
North Ossetia

Sphagnum mires on the Greater Caucasus are rare, characterized by the presence of relict plant communities of glacial age and are in a stage of degradation. The study of Sphagnum of Chefandzar and Masota mires is carried out for the first time. Seven species of Sphagnum are recorded. Their distribution and frequency within the North Caucasus are analyzed. Sphagnum contortum, S. platyphyllum, S. russowii, S. squarrosum are recorded for the first time for the study area and for the flora of North Ossetia. The other mosses found in the study area are listed.

An Epistemological Criticism of Social Entrepreneurship: Is Social Entrepreneurship a Sound Scientific Field of Research

2018 ◽  
Author(s):  
Amir Forouharfar
Keyword(s):  
Social Entrepreneurship ◽  
Social Constructivism ◽  
Social Epistemology ◽  
American English ◽  
Meta Analysis ◽  
Research Question ◽  
Knowledge Structure ◽  
Scientific Field ◽  
The Other ◽  
First Time

The paper was shaped around the pivotal question: Is SE a sound and scientific field of research? The question has given a critical tone to the paper and has also helped to bring out some of the controversial debates in the realm of SE. The paper was organized under five main discussions to be able to provide a scientific answer to the research question: (1)<b> </b>is “social entrepreneurship” an oxymoron?, (2) the characteristics of SE knowledge, (3) sources of social entrepreneurship knowledge, (4) SE knowledge: structure and limitations and (5) contributing epistemology-making concepts for SE.<b> </b>Based on the sections,<b> </b>the study relied on the relevant philosophical schools of thought in <i>Epistemology </i>(e.g. <i>Empiricism</i>, <i>Rationalism</i>, <i>Skepticism</i>, <i>Internalism</i> vs. <i>Externalism</i>,<i> Essentialism, Social Constructivism</i>, <i>Social Epistemology, etc.</i>) to discuss these controversies around SE and proposes some solutions by reviewing SE literature. Also, to determine the governing linguistic discourse in the realm of SE, which was necessary for our discussion,<i> Corpus of Contemporary American English (COCA)</i> for the first time in SE studies was used. Further, through the study, SE buzzwords which constitute SE terminology were derived and introduced to help us narrowing down and converging the thoughts in this field and demarking the epistemological boundaries of SE. The originality of the paper on one hand lies in its pioneering discussions on SE epistemology and on the other hand in paving the way for a construction of sound epistemology for SE; therefore in many cases after preparing the philosophical ground for the discussions, it went beyond the prevalent SE literature through meta-analysis to discuss the cases which were raised. The results of the study verified previously claimed embryonic pre-paradigmatic phase in SE which was far from a sound and scientific knowledge, although the scholarly endeavors are the harbingers of such a possibility in the future which calls for further mature academic discussion and development of SE knowledge by the SE academia.

A Nabatean port on the Red Sea: note on the pottery finds from al-Qusayr (al-Wajh, Saudi Arabia)

2020 ◽  
Author(s):  
Caroline Durand
Keyword(s):  
Saudi Arabia ◽  
19Th Century ◽  
Red Sea ◽  
Point Of View ◽  
The Other ◽  
Trade Routes ◽  
Other Hand ◽  
Roman Egypt ◽  
Pottery Sherds ◽  
First Time

Al-Qusayr is located 40 km south of modern al-Wajh, roughly 7 km from the eastern Red Sea shore. This site is known since the mid-19th century, when the explorer R. Burton described it for the first time, in particular the remains of a monumental building so-called al-Qasr. In March 2016, a new survey of the site was undertaken by the al-‘Ula–al-Wajh Survey Project. This survey focused not only on al-Qasr but also on the surrounding site corresponding to the ancient settlement. A surface collection of pottery sherds revealed a striking combination of Mediterranean and Egyptian imports on one hand, and of Nabataean productions on the other hand. This material is particularly homogeneous on the chronological point of view, suggesting a rather limited occupation period for the site. Attesting contacts between Mediterranean merchants, Roman Egypt and the Nabataean kingdom, these new data allow a complete reassessment of the importance of this locality in the Red Sea trade routes during antiquity.

Status of Family Fissidentaceae in Gujarat

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar
Keyword(s):  
Distinct Species ◽  
The State ◽  
The Other ◽  
Land Plants ◽  
Reproductive Structures ◽  
The Family ◽  
The Status ◽  
Vegetative Characters ◽  
First Time ◽  
Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

scholarly journals First Report of blaNDM-1 Bearing IncX3 Plasmid in Clinically Isolated ST11 Klebsiella pneumoniae from Pakistan

2021 ◽  
Vol 9 (5) ◽  
pp. 951
Author(s):  
Hazrat Bilal ◽  
Gaojian Zhang ◽  
Tayyab Rehman ◽  
Jianxion Han ◽  
Sabir Khan ◽  
...  
Keyword(s):  
Sequence Type ◽  
The Other ◽  
High Rate ◽  
Antibiotics Resistance ◽  
New Delhi ◽  
Molecular Type ◽  
Plasmid Analysis ◽  
First Time ◽  
Encoding Genes ◽  
Sequence Types

The New Delhi Metallo-β-lactamase (NDM) is among the most threatening forms of carbapenemases produced by K. pneumoniae, well-known to cause severe worldwide infections. The molecular epidemiology of blaNDM-1-harboring K. pneumoniae is not well elucidated in Pakistan. Herein, we aim to determine the antibiotics-resistance profile, genes type, molecular type, and plasmid analysis of 125 clinically isolated K. pneumoniae strains from urine samples during July 2018 to January 2019 in Pakistan. A total of 34 (27.2%) K. pneumoniae isolates were carbapenemases producers, and 23 (18.4%) harbored the blaNDM-1 gene. The other carbapenemases encoding genes, i.e., blaIMP-1 (7.2%), blaVIM-1 (3.2%), and blaOXA-48 (2.4%) were also detected. The Multi Locus Sequence Typing (MLST) results revealed that all blaNDM-1-harboring isolates were ST11. The other sequence types detected were ST1, ST37, and ST105. The cluster analysis of Xbal Pulsed Field Gel Electrophoresis (PFGE) revealed variation amongst the clusters of the identical sequence type isolates. The blaNDM-1 gene in all of the isolates was located on a 45-kb IncX3 plasmid, successfully transconjugated. For the first time, blaNDM-1-bearing IncX3 plasmids were identified from Pakistan, and this might be a new primary vehicle for disseminating blaNDM-1 in Enterobacteriaceae as it has a high rate of transferability.

scholarly journals On the embedding of a group in a join of given groups

1974 ◽  
Vol 17 (4) ◽  
pp. 434-495 ◽  
Author(s):  
P. Hall
Keyword(s):  
Countable Group ◽  
The Other ◽  
Other Hand ◽  
First Time ◽  
Fundamental Paper

1. In their fundamental paper of 1949, Higman, Neumann and Neumann proved for the first time that a countable group can always be embedded in some 2-generator group: [1], Theorem IV. Two kinds of improvement of this result have recently appeared. In [4], Theorem 2, Dark has shown that the embedding can always be made subnormally. On the other hand, in [2], Theorem 2.1, Levin has shown that the two generators can be given preassigned orders m > 1 and n > 2; and in [3], Miller and Schupp prove that the 2-generator group can also be made to satisfy several additional requirements, such as being complete and Hopfian.

scholarly journals 1. On the Computation of the Strengths of the Parts of Skeleton or Open Structures

1872 ◽  
Vol 7 ◽  
pp. 575-576
Author(s):  
Edward Sang
Keyword(s):  
The Other ◽  
Open Structures ◽  
First Time ◽  
General Configuration

The first part of the paper is devoted to the computation of the strengths of the parts of a structure destined to resist given strains, taking into account, along with those strains, the unknown weights of the parts. The results obtained by this process necessarily give the best possible arrangement of the strengths, since, if any one part were made weaker, the whole structure would be weakened; or, if a part were made stronger, the unnecessary weight thus thrown upon the other parts would also go to weaken the fabric. It is believed that this investigation has now been given for the first time.It was pointed out that this method enables us to determine the utmost limit of magnitude of a structure having a given general configuration.

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