38 The Cartilaginous Fishes of Lower Bengal. [No. 1, 



unite, on either side of which the outline describes merely a slight 

 concavity.* 



16. TETGOisr marginattjs, nobis, n. s. Grey above, buffy- white 

 below with a dark border except in front ; the tail If- the length of 

 the disk. A large species, adults of which are mostly quartered when 

 brought to the bazar, and then more or less sliced up by the dealers, 

 so that it is difficult to examine them properly. Breadth of one 

 52 in., with tail 83 in.: distance of eyes apart 7 in.f Form a trifle 

 longer than broad, or shorter than broad if the length be measured 

 from front to base of tail. In adults the small limpet-shaped tuber- 

 cles are disposed not only over the entire upper surface, but also on 

 the broad dark margin of the lower-parts (from which the species 

 derives its trivial name) : they are larger and more closely set along 

 the middle, though for the most part not in absolute contact, and are 

 gradually smaller and less crowded laterally, but again become more 

 crowded towards the margin ; and there is commonly an irregular 

 range of pointed tubercles larger than the rest on either side, about 

 3 in. from the median line in adults. Tail tuberculated all round to 

 within 2\ in. of its base underneath, and having scattered and pointed 

 tubercles much larger than the rest above, from its base to the large 

 caudal spine. The colour of this fish is a light albescent-brown 

 above, with still a faint blackish wash ; white, with more or less of a 

 buffy tinge, below, and a broad dark margin to the lower-parts except 

 in front, but including the ventrals, this border consisting of numerous 

 large round spots on its inner edge, some wholly and others partially 

 detached from the rest ; a few irregular spots are also generally 

 scattered upon the pectorals. The under-surface of the tail is white, 

 with similar scattered dark spots, which gradually become more 

 numerous and coalescent till they assume a marbled appearance, and 

 the apical half of the tail is wholly dark. This dark colour is more 

 intense in the young, approaching more or less to black : whereas in 



* I presume this form to be characteristic of the division. In the Medical 

 College specimen the peak is stretched out of all shape. However, in a very large 

 example just added to the museum, the narrow medial peak projected more than 

 in the young. 



f A large specimen has just been presented to the Society, fresh, by Raja 

 Radakhant Deb, 5 ft. across ; tail imperfect. 



