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



dorsal tubercle and another behind it, surrounding which is a group 

 of small tubercles that might be covered by a crown-piece, except 

 anteriorly where a few are scattered along the dorsal line and between 

 the eyes, — the rest, including the tail, being wholly naked. A slight 

 marbled appearance on the tail beyond the spine, but no distinct 

 alternating bands. Another, only 10 in. to base of tail, has the 

 dorsal tubercles fully developed, and a band of them upon the tail 

 not reaching so far as the caudal spine. In a specimen 13 in. long, 

 the tail measures 47 in. ; and the tubercles on the tail (now that it 

 is dry and shrunk) appear to extend two-thirds round its base anterior 

 to the spine ; but in the tail of 6 ft. long before noticed, the upper 

 half only is tuberculated anterior to the spine. The usual central 

 dorsal tubercle, with commonly one smaller before and another behind 

 it ; and the small tubercles, which extend over the medial third of 

 the dorsal surface (as also in Te. Bleekeei), are more uniform in 

 size than in the other species. In one specimen of a tail, which I 

 assign to this particular species with some hesitation, there are two 

 sharp erect prickles in the median line towards its base, and others 

 beyond the spine. A commoner species than the last. 



21. Tr. Russellii, Gray ; young figured in Hardwicke's III. 

 2nd. Zool. : Tr. Gerrardii, Gray, Brit. Mus. Catal., still younger. 

 A beautiful species, covered above with large round dark spots, a few of 

 which are generally confluent : tail banded throughout. Anterior 

 peak more acute than in Tr. Ellioti, less so than in Tr. Bleekeei. 

 In large specimens (3 ft. across) the spots continue as strongly 

 marked as in the young, and are then more or less pale-centred, 

 forming distinct rings more or less perfect in some specimens. But 

 these markings, however vivid in the recent fish, are apt to disappear 

 in old stuffed specimens, the tail-bands being longest retained ; and a 

 smooth young fish, with the spots on the upper surface obliterated, 

 but retaining the bands on the tail, suits the description of Tr. 

 Gerrardii, Gray. At the age figured by Hardwicke, the tubercles on 

 the back are sparse and heart-shaped, and a single line of them (pro- 

 longed more or less into backward-curving prickles) is continued along 

 the median line of the tail as far as its spine. These are retained in 

 a specimen 12 in. in length (to base of tail) ; but in another of the 

 same size tiny had disappeared — or perhaps had never made their 



