The Embryology of Chlamydoselachus 553 



In 1898, Nishikawa gave us our first definite data on the inequality in structure and 

 function of the oviducts. He states that the left one is always rudimentary but that 

 "The right oviduct is very much distended and contains from 3 to 12 eggs, these numbers 

 being the limits observed in 7 specimens". 



Hawkes (1907) notes that the right oviduct in her specimens was much larger than 

 the left. So Smith found and graphically shows for three fish in Text'figures 11, 14 and 15 

 herein. The uteri of Hawkes's specimens contained no embryos; nor did Smith's. Since 

 Smith's specimens were brought from Japan by Dean, it is probable that, when the two 

 gravid fish were caught, the uteri (Text'figures 14 and 15) were opened to get the eggs and 

 embryos for him. 



Deinega (1925) was evidently under the impression that Chlamydoselachus, like 

 most other sharks, should carry eggs and embryos in both uteri. He states that in his 

 specimen "the left oviduct, in its exterior form, produces the impression of being under' 

 developed or of being in a temporarily non 'functioning condition". However, the right 

 oviduct, a short distance behind its large shell gland, "suddenly expands into a rather 

 capacious sac". It contained no eggs. 



Dean's notes afford both negative and positive evidence of the differential function' 

 ing of the oviducts. Thus of a 1565'mm. fish he says, "left ovid. greatly reduced, eggs 

 fr. r."; of a 1575'mm. female he notes "left ovid. greatly reduced, no dilat. uterus"; 

 another 1565'mm. fish had "1. ovid. small, small uterus". On the other hand Dean 

 records the taking of various eggs and embryos from the right oviducts of specimens of 

 Chlamydoselachus captured in the Sagami Sea. From one fish he got two eggs and from 

 another three. Then he notes "8 in female" — oviduct not recorded but presumably the 

 right. As seen above, and as will be noted later, had it been the left he would pretty 

 surely have so stated. In the records of his Japanese collector are listed three eggs from 

 right oviduct of one fish, five from another, and seven from the right oviduct of each of 

 two other females. These last eggs were all in early stages and had egg shells. 



Distention of Gravid Right Uterus. — Unfortunately there are little data available 

 as to the size attained by the right uterus as gestation goes forward to birth. However, 

 there are two ways of studying the problem : one by bringing together the few scattered 

 measurements of the organ, the second by setting forth the number of eggs and embryos 

 (with their measurements) found in the uterus. These compilations will now be made. 



Measurements of Gravid Right Uterus. — Hawkes (1907) states that the oviducts 

 begin to enlarge when they reach the level of the anterior end of the colon. On the left 

 the diameter is increased gradually and only about four'fold, but "on the right, the en' 

 largement is sudden and very apparent, the diameter increasing 14 to 15 times". She 

 nowhere speaks of finding embryos in the uterus. 



Deinega's description (1925) of the reproductive system is very brief. But the two 

 things that the reader gets from it are that the left oviduct "produces the impression of an 

 underdeveloped oviduct or a temporarily non'functioning one". While the right one in its 

 posterior part "suddenly expands in the form of a rather capacious sac about 130 mm. in 



