igiQ-] 1"- Southwell & B. Prashad : Studies of Indian Fishes. 223 



single fully developed egg-case, besides a large quantity of yellow- 

 ish fluid secretion surrounding a number of eggs. 



The egg-cases when fresh were of a light yellowish colour. 

 The specimens preserved in spirit are dark yellow, the margins 

 being still darker, whereas the sides are brownish. It is of a 

 quadrangular shape, much broader in the middle than at the ends. 

 Two of the four sides of this quadrangular structure are very 

 much narrower than the other two, and hence the longer sides, 

 instead of being straight, curve inwards near the two ends, and 

 in a contracted specimen, seem to meet each other. In the middle, 

 the egg-case is much thicker owing to the egg and the yolk 

 contents. Near the upper and lower edges the two surfaces of the 

 chitinous case meet and are united to form a flat surface, which 

 in contracted specimens is wrinkled. The four angles are prolonged 

 into small thin filaments, which, compared with those of the Euro- 

 pean species of dogfishes, are rudimentary structures, and would 

 be of little use for the attachment of the egg-cases to foreign objects 

 in the sea after these have been laid. But another structure of a 

 different type, and probably more suited to the conditions under 

 which these fishes live, has been developed. Attached to one of the 

 longer sides is a very long (134 mm.) and thick cord of a silky 

 material. Where it joins the egg it broadens out and is attached 

 along a large area on the side. It then gradually tapers to a 

 cylindrical cord. This long cord would be very useful for moor- 

 ing the egg-cases to any object at the bottom of the sea. A few 

 strands of a white colour also arise from two places on the oppo- 

 site side. 



The two specimens are of the same size, the measurements of 

 one of these are as follows : — 



Maximum length . . . . . . 6o-8 mm. 



,, breadth . . . . . . 31-1 mm. 



,, thickness . . . . 16 5 mm. 



IV. Intra-Uterine Embryos. 



In this part of the paper we have given descriptions of the 

 intra-uterine embryos of a number of Indian Elasmobranchs. In 

 addition to the material described we had before us a number of em- 

 bryos as to the specific identification of which we are not certain. 

 These, however, v»'ere found to be of great use in elucidating certain 

 general conclusions which are given at the end of this paper. 



Scoliodon walbeehmi, Bleeker. 

 (PI. XVII, figs. I, 2, 4, 7 and 8.) 



1889. Cai'cliarins roalbeclimi. Day, Fanii. Brit, hid.. Fishes, 1, p. lo, 

 1913. Scoliodon ivalbeelimi, (iarman, Metn. Mus. Camp. Zool. Harvard 

 XXXVI, p. 112. 



In the young embryo 106 mm. long the head is not at all 

 elongate and the snout much less pointed than in the adult. The 



