Memoirs: Notes on Protodrilus

1931 ◽  
Vol s2-74 (294) ◽  
pp. 303-320
Author(s):  
E. S. GOODRICH
Keyword(s):  
Coelomic Epithelium ◽  
Sperm Duct ◽  
Morphological Nature

The nephridium of Protodrilus flavocapitatus is described in detail. With its long-coiled canal and small projecting nephridiostome it is shown to be more complicated than hitherto supposed. The sperm-duct of the male has a ridged ciliated coelomostome and represents a coelomoduct or possibly a nephromixium. It is argued that the ‘brachynephridia’ and sperm-ducts of all Protodrilids are of the same morphological nature. The fate of the coelomoduct is related to the mode of emission of the genital products. In the female of Pr.flavocapitatus , which sheds the ripe ova by dropping off posterior segments, the coelomoducts have been lost in all the segments, and in the male in all the segments excepting the eleventh. Remains of the coelomostomes are perhaps represented by the ciliation of the coelomic epithelium in the genital segments of the female. It is maintained that Protodrilus is dioecious, that the female may be early inseminated by the male, that copulation must take place, and that the dorsal glands are perhaps concerned in the process. Ripe spermatozoa only are found in the female, and the so-called stages in ‘cystospermatogenesis’ are probably stages in the phagocytosis of superfluous spermatozoa.

Sex chimaerism, fertility and sex determination in the mouse

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 311-325 ◽  
Author(s):  
C.E. Patek ◽  
J.B. Kerr ◽  
R.G. Gosden ◽  
K.W. Jones ◽  
K. Hardy ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sertoli Cells ◽  
Leydig Cells ◽  
Sex Chromosome ◽  
Tunica Albuginea ◽  
In Situ Hybridisation ◽  
Ovarian Surface Epithelium ◽  
Surface Epithelium ◽  
Seminiferous Tubules ◽  
Coelomic Epithelium

Adult intraspecific mouse chimaeras, derived by introducing male embryonal stem cells into unsexed host blastocysts, were examined to determine whether gonadal sex was correlated with the sex chromosome composition of particular cell lineages. The fertility of XX in equilibrium XY and XY in equilibrium XY male chimaeras was also compared. The distribution of XX and XY cells in 34 XX in equilibrium XY ovaries, testes and ovotestes was determined by in situ hybridisation using a Y-chromosome-specific probe. Both XX and XY cells were found in all gonadal somatic tissues but Sertoli cells were predominantly XY and granulosa cells predominantly XX. The sex chromosome composition of the tunica albuginea and testicular surface epithelium could not, in general, be fully resolved, owing to diminished hybridisation efficiency in these tissues, but the ovarian surface epithelium (which like the testicular surface epithelium derives from the coelomic epithelium) was predominantly XX. These findings show that the claim that Sertoli cells were exclusively XY, on which some previous models of gonadal sex determination were based, was incorrect, and indicate instead that in the mechanism of Sertoli cell determination there is a step in which XX cells can be recruited. However, it remains to be established whether the sex chromosome constitution of the coelomic epithelium lineage plays a causal role in gonadal sex determination. Male chimaeras with XX in equilibrium XY testes were either sterile or less fertile than chimaeras with testes composed entirely of XY cells. This impaired fertility was associated with the loss of XY germ cells in atrophic seminiferous tubules. Since this progressive lesion was correlated with a high proportion of XX Leydig cells, we suggest that XX Leydig cells are functionally defective, and unable to support spermatogenesis.

scholarly journals The Histology and Activities of the Tube-feet of Echinocyamus pusillus

1959 ◽  
Vol s3-100 (52) ◽  
pp. 539-555
Author(s):  
DAVID NICHOLS
Keyword(s):  
Sea Urchin ◽  
Nerve Plexus ◽  
Asterias Rubens ◽  
Coelomic Epithelium ◽  
Sensory Cilia ◽  
Thin Walled ◽  
Postural Movement ◽  
Tube Feet

The histology of the suckered, buccal sensory, and respiratory tube-feet and their ampullae, where they occur, of the clypeasteroid sea-urchin Echinocyamus pusillus is described. Each suckered tube-foot possesses two sets of special muscles for attachment and detachment, a ring of mucous glands to assist in attachment, and a ring of sensory cilia. The stem retractors are in four columns, whose differential contraction provides the means of postural movement relative to the test. The ampullae of these tube-feet are exceedingly thin-walled, apparently musculo-epithelial, with anastomosing contractile elements. The canal between tube-foot and ampulla contains a swollen coelomic epithelium which may help to maintain the nerve relationships of the system. The activity of the suckered tube-feet is compared with that of the tubefeet of the starfish, Asterias rubens. The buccal tube-feet, larger than the suckered tube-feet, have large disks underlain by a thick nerve plexus supported by transverse fibres; a ring of sensory cilia surrounds the disk. They have no mucous glands and no suckers, and are presumably entirely sensory, probably both tactile (the cilia) and chemoreceptive (the disk). The respiratory tube-feet are thin-walled sacs, the walls consisting of an outer ciliated and an inner non-ciliated (coelomic) epithelium with cross-connexions for support; where the coelomic epithelium lines the pair of canals through the test it is heavily ciliated. In the specializations of its tube-feet this urchin is shown to share some features with the regular urchins and others with the spatangoids.

scholarly journals Memoirs: On the Nephridiostome of Lumbricus

1932 ◽  
Vol s2-75 (297) ◽  
pp. 165-179
Author(s):  
EDWIN S. GOODRICH
Keyword(s):  
Connective Tissue ◽  
Lumbricus Terrestris ◽  
Coelomic Epithelium ◽  
Lower Lip ◽  
Excretory Organ ◽  
Marginal Cells ◽  
Straightforward Interpretation

The structure of the nephridiostome of Lumbricus terrestris L. is described, including the anatomical relations of canal, gutter, central, and marginal cells and their cytological characters. The extent and relation of the lower lip to other parts are also described. An account of the development of the nephridium is given from the stage when the rudiment still bears a single large ‘funnel-cell’ bulging forwards through the septum into the coelom. The whole nephridiostome (excluding the covering of coelomic epithelium and the connective tissue) is shown to arise from the nephridial rudiment, wholely or partly from that part of the funnel-rudiment which is derived from the ‘funnel-cell’. Upper, lateral, and lower lips are all developed from the funnel rudiment in which the lumen becomes pierced. There is no evidence that the coelomic epithelium contributes any part of the true nephridiostome. The view sometimes put forward that the excretory organ of Lumbricus is a nephromixium is not founded on sound evidence, and is opposed to the simple straightforward interpretation of its morphology which follows most naturally from the facts and a comparison with lower forms.

THE MORPHOLOGICAL NATURE OF TEOPOD CORN

1929 ◽  
Vol 20 (7) ◽  
pp. 325-330 ◽  
Author(s):  
PAUL WEATHERWAX
Keyword(s):  
Morphological Nature

Induction of potential for sperm motility by bicarbonate and pH in rainbow trout and chum salmon

1988 ◽  
Vol 136 (1) ◽  
pp. 13-22 ◽  
Author(s):  
S. Morisawa ◽  
M. Morisawa
Keyword(s):  
Rainbow Trout ◽  
Seminal Plasma ◽  
Magnesium Chloride ◽  
Chum Salmon ◽  
Ph Value ◽  
Bicarbonate Concentration ◽  
Sodium Potassium ◽  
Sperm Duct ◽  
Calcium Magnesium ◽  
Immotile Spermatozoa

Spermatozoa of rainbow trout and chum salmon, which have no potential for motility in the testis, acquire that potential in the sperm duct. This paper demonstrates that there is little difference between the levels of sodium, potassium, calcium, magnesium, chloride and osmolality of the seminal plasma in the testis and in the sperm duct. However, the bicarbonate concentration of the seminal plasma and the pH value of semen were higher in the sperm duct than in the testis. When immotile spermatozoa obtained from the testis were incubated in artificial seminal plasma with a high pH and containing HCO3-, spermatozoa became motile within 1 h. These results suggest that spermatozoa of salmonid fish acquire the potential for motility as a result of the increase in seminal bicarbonate concentration and pH that occurs as spermatozoa pass from the testis to the sperm duct.

The Fine Structure of the Respiratory Tree in Cucumaria

1964 ◽  
Vol s3-105 (69) ◽  
pp. 7-11
Author(s):  
WILLIAM L. DOYLE ◽  
G. FRANCES McNIELL
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Secretory Activity ◽  
Muscle Fibres ◽  
Coelomic Epithelium ◽  
Free Surfaces ◽  
Respiratory Tree ◽  
Synchronous Contraction

The delicate tubules of the respiratory tree consist of 4 layers: a lining epithelium, a thick mucoid layer containing collagenous filaments, a smooth muscle net, and a coelomic epithelium. The free surfaces of both epithelia have well developed plasmodesms. Amoebocytes are present in all layers and the spherules of one type are considered to be precursors of the mucoid substance; another amoebocyte may be a fibroblast. Perpendicularly oriented smooth muscle fibres, as well as those parallel to each other, are linked by desmosomes ensuring synchronous contraction. Secretory activity is evident in distended cisternae of the endoplasmic reticulum of certain epithelial cells and in the vacuoles of the lining epithelium.

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