96 



T. NISHIKAWA. 



ly brought to the Tokyo market by fishermen from Böshü, on the eastern side of 

 the Bay of Tokyo, and also that it is sometimes, though very rarely, caught by 

 the fishermen of Misaki. The ordinary fishing apparatus must be ineffective 

 against such sharp teeth, and it must be largely by chance that specimens of 

 this interesting shark are occasionally brought up from the deep. Nevertheless 

 I have been able to obtain a few developmental stages, and I propose in this 

 paper to make a few notes on them. 



Chlamydoselachu8 anguineus is viviparous, and the breeding season is spring, 

 extending from about the end of March to the beginning of June. The left ovi- 

 duct is always rudimentary,* but the nidamental gland of the right side is better 

 developed than that of the opposite side. The right oviduct is very much dis- 

 ten ted and contains from 3—12 eggs, these numbers being the limits observed in 

 seven specimens. The oviduct is only about 60 cm. long, and one can imagine 

 the degree of its distension when as many as twelve eggs, each 11 — 12 cm. long, 

 are contained in it. 



The egg is ellipsoidal, and varies between 6.5 — 7.5 cm. in its shorter diameter 

 and 10.2 — 12.4 cm. in its longer diameter, the measurement being made in the 

 physiological solution of salt (fig. 1 & 2). It bears a stumpy excrescence at one 

 end and a slightly recurved flattened process, about 3.5 cm. long, at the other. 

 The capsule is light brown and transparent. The space between the capsule 

 and the yolk-sac is, in earlier stages, very insignificant, being confined mostly 

 to the two p )le3 of the egg, and is filled with the white, which is very fluid. 

 The yolk is of a pinkish color, and the yolk-sac is very delicate. Hence it fre- 

 quently happens that the contents of an egg get all mixed np during transporta- 

 tion. 



The blastoderm has a yellowish red color, as in other sharks. The earliest 

 stage that I have been able to obtain was nearly circular in form and had the 

 diameter of 1.3 mm. The next stage was a blastula, with a distinct segmentation 

 cavity, whose floor was bounded by what has been termed " periblast " with fine, 

 ly granular yolk, and merocytes, with vacuolated cytoplasm, due perhaps to the 

 dissolution of the contained oil drops, and many nuclei. One end of the blastula 

 was thicker than the other, and is evidently the " embryonic end " of Balfour, 



* When no eggs are contained there is no perceptible difference in size between the two 

 oviducts. — S. G. 



