The J^atural History of the Frilled Shar\ 303 



352, 390 (yolk-sac 70x100)" — 12.5, 13.85 and 15.35 in. respectively. Our 6 embryos 

 (Dean's material) have been in preservative for about 30 years; the yolks are much shrunk- 

 en, and are almost as solid and hard as stones. The smallest embryo (190 mm., 7-5 in.) 

 has had the yolk-sac opened and the yolk removed. The 200'mm. (7.9-in.) embryo has a 

 yolk-sac measuring 57x75 mm. (depth and length); the 245-mm. (9.7'in.) young has a 

 yolk-sac measuring 60x74 mm.; for the 305-mm. (12-in.) specimen, the yolk-sac is 57 X 

 83; in the 320-mm. (12.6-in.) fish, the yolk-sac (which has been cut off but preserved in 

 the same jar) measures 64x76 mm; and in our largest embryonic specimen, 374 mm. (14.7 

 in.) long, the yolk-sac is 51mm. deep by 73 long. 



This is a huge yolk-mass for any shark's egg, especially when we consider that the 

 volume of this yolk has been diminished by furnishing food for the growth of an embryo 

 14-7 inches in length, and undoubtedly over a year in age. 



In the literature we find but two references to the eggs and young of Chlamydoselachus, 

 other than those already mentioned. Ziegler (1908) says that he had three small embryos, 

 two of 25 and one of 75 mm. long. He does not give measurements of the yolk-sac. How- 

 ever, his student Brohmer (1909) worked on the head of the larger embryo and his text- 

 fig. 1 shows egg and embryo ''in naturlicher Grosse." The yolk-sac in this figure 

 measures 60 x 110 mm. It is the only representation known to us of an entire egg, other 

 than those found in Dean's drawings and in Nishikawa's photograph and drawings (Text- 

 figures 2 and 24). 



From the data presented, it is certain that gestation lasts at least one year and prob- 

 ably longer. When one realises that these sharks live at depths of 1500 to 2500 ft., where 

 the temperature is low, one might infer that growth of the embryo is slow as it is in fish 

 embryos reared at low temperatures at the surface; but we have no data concerning the 

 effect of pressure on the rate of development of aquatic organisms. Further, taking into 

 consideration the large si2;e of the yolk-sac in the second year, it seems possible that hatch- 

 ing may not take place until at least the second summer following impregnation, and indeed 

 that it may not take place till after the little shark is quite two years old. 



NOMENCLATURE OF CHLAMTDOSELACHUS 



Generally, in fishes as in other animals, various describers have given different names 

 to one and the same animal, hence it becomes necessary to prepare an extensive list of 

 names, the synonymy of modern authors. However, Chlamydoselachus is such a definitely 

 characterised fish that only two attempts have been made to change its name from that 

 first given it. These will be recounted in their proper places. 



SCIENTIFIC NAMES 



In giving this fish the name Chlamydoselachus anguineus, Garman exemplified the 

 best ideal of nomenclature — which is to make the name accurately and briefly describe 

 the thing named. Literally translated, this name means 'snake-Hke cloak [-gilled] shark,' 

 and how correct this is may be seen in Figure 1, plate I. The body is attenuate and 



