1907.] ANATOMY OP CHLAMYDOSELACHUS. 477 



whether any glands homologous with utei'ine glands of higher 

 forms are present, but it is highly probable that all the granular 

 columnar cells secrete a fluid. The musculo-fibrous tissue of the 

 uterine wall is greatly thickened owing to an increase of con- 

 nective tissue in which connective -tissue corpuscles abound *. 



The kidney in the female is thin dorso-ventrally and of irregular 

 breadth. It extends from the region of the oviducal gland to the 

 end of the body-cavity, gradually widening as it passes backwards 

 in a sinuous line. The sinuosity is due to the arrangement of 

 some of the dorsal muscles. Cephalad to the kidney and ap- 

 parently unconnected with it, there is an irregular body (1*5 cm.) 

 which extends somewhat beyond the end of the abdominal cavity. 

 This is probably the head kidney (pronephros ?), which in the 

 adult has retained its position in the I'egion to which the coelom 

 extended in the embryo. 



There are two very small cloacal apertures for the urinary 

 sinuses (text-fig. 139 B, U.S'.) in the specimen examined, although 

 Garman only found one in his (1. p. 20). They are situated 

 in the median line near the external opening of the cloaca. The 

 openings are near together but can hardly be mistaken for 

 one. Each aperture passes into an expanded chamber (U.S.) 

 with laminated walls, the lumen of which has a diameter of 5 mm. 

 in the cloacal region. The first portion of the sinus is embedded 

 in the thick cloacal walls. Each sinus extends forwards for a 

 distance of 6 cm. beyond the cloaca along the inner side of the 

 kidney, but in front of this point it lies near the oviduct, at a 

 distance from the kidney varjdng from 1 to 2 cm. The same 

 mesentery which supports the oviduct also supports the urinaiy 

 sinus and the mesonephric ducts. The latter pass from the 

 kidney at regvilar distances, there being approximately one to 

 each myotome. 



In the female cloaca the rectal aperture is displaced to the 

 right, and the same deviation, but to a much less degree, occurs 

 also in the male. 



The Male. — -In the male there are two urogenital apertures 

 (text-fig. 139 A, Ug.), each of which is the outlet of an oval uro- 

 genital sinus (B.), which Giinther described as a urinary bladder. 

 The sinus communicates by a very small aperture with a second 

 and larger chamber (R.8.), which possibly functions as a seminal 

 vesicle, and in front has opening into it the vas deferens or 

 mesonephric duct (Y.D.). The vas deferens has one or more pro- 

 jecting spiral folds, which run from one end of the duct to the 

 other. For the last 10 cm. of the length of the duct the folds were 

 very obvious, but from this point forwards th(iy become almost 

 invisible to the naked eye. The folds are so close together in the 



* Since this paper was read, I have received a letter from Mr. Kumakichi Aoki, of 

 the Zoological Station at Miura Misaki, stating, in answer to some questions, that 

 eggs are not laid and that he has latelj' had two females, each of which contained 

 five embryos, in one case measuring one foot each and in the other one inch. Each 

 very young embryo with its large yolk-sac was surrounded by a gelatinous sac, no 

 doubt the remnant of the ^^% envelopes. 



