I9I9-J '^- vSouTHWELi. & B. Prashad : Studies of Indian Fishes. 233 



Ceylon coast, on 7th November, igro. There was a single speci- 

 men in the right oviduct. 



This specimen, though evidently much older than the ones 

 described by Wood Mason and Alcock. has a vestige of a yolk-sac 

 and yolk-stalk, whereas the specimens described by these authors 

 had no trace of a yolk-sac or yolk-stalk (p. 364, loc. cit.). 



Aetomylacus nichofii (Schneider), 

 (PI. XIX, figs. 4, 4a.) 



1909. Myliobatis iiienliofii, Annandalc, op, cit., p. 51. 



1913. Aetomvlaeiis nichofii, Garman, Mem. Mus. Comp. Zool, Harvard, 



XXXVI, p. 436. 

 igi6. Aetomylaevs nichofii, Chaudhuri, op. cit., V, p. 413. 



This is a very interesting stage in that it is slightly more 

 advanced in the absorption of the yolk-sac and the yolk-stalk 

 than the embryo of Pteroplatea poecihira described above. 



Only the anterior part of the head can be said to be distinct 

 from the disc (figs. 4, 4a), A horn or tentacle nearly 2 mm. in 

 length projects slightly in front of the spiracles and below the 

 eyes. The rostral fin has a fringe along its posterior margin. 



The shape of the spiracles is very characteristic (fig. 4^) and 

 brings into mind the peculiar modification brought about for the 

 large trophonemata from the mother's uterus pouring their secre- 

 tion into the pharynx. The upper margin of the skin which forms 

 a covering over the spiracles is raised upwards and forwards. 



The abdomen is very much swollen ventrally owing to the 

 large colon, which can be seen through the skin. The dorsal fin 

 arises just at the origin of the tail. The claspers in the male 

 specimen are small rod-like structures tapering to a point at their 

 free end ; they measure 6 mm. in length. 



The body is quite smooth. The yolk-sac and the yolk-stalk 

 have already been very largely absorbed. 



The embryos have a brownish colour. In one of them a dark 

 brown line at a little distance from the margin of the disc and 

 closely following its outline is very distinctly to be seen. The long 

 tail has a deep chocolate colour banded with yellowish rings, 

 ventrally its distal portion is entirely yellowish. 



Measurements of a male specimen: — 



Breadth of the disc .. in mm. 



Mouth to vent . . . . 47 mm. 



Length of snout . . . . 8'5 mm. 



Rostral fin . . . . 11 mm. X 7 mm. 



Interorbital space .. 16*5 mm. 



Size of spiracle . . .. 13 mm. X 6 mm. 



Tail . . . . . . 235 mm. 



Diameter of yolk-sac .. 15 mm. 



Yolk-stalk . . . . 0*4 mm. 



