REPORT ON THE PELAGIC FISHES. 25 



I note the following details for specific descriptions : — 



Bregmaceros macclellandii, Thompson (PL III. figs. A, B). 



Bregmaceros macdellandii, Thompson. 



Catloptiium rnirum, Richards. 



Bregmaceros macclellandii (syn. Calloptiliim miruni), Gthr. 



Asthenurus atripinnis, TickeE. 



Bregmaceros atrijjinnis, n. sp., Day. 



Bregmaceros atripinnis (excl. synon.), and Bregmaceros macclellandii, Day. 



D. 1 I 16-19+:c+ 15-21. A. 22-30 + .x + 20-22. V. 5-6. L. lat. 64-70. 



L. transv. 14-16. 



In an adult specimen from the Indian Ocean (PI. III. fig. A) 4^ inches long, the 

 greatest depth of the body is below the origin of the soft dorsal fin, aud contained five 

 and a half times in the total length, without caudal. The head is small, short and broad, 

 its length being contained six and a half times in the total length. The eye is rather 

 large, two-sevenths of the length of the head, and equal to the width of the interorbital 

 space ; its upper half is covered with a transparent membrane. Snout short, shorter 

 than the eye, obtuse, rounded, the lower jaw being received within the upper. Mouth of 

 moderate size, the maxillary not extending to the hind margin of the orbit. Teeth in 

 the jaws very minute, and those on the head of the vomer scarcely perceptible. The 

 isthmus is broad and muscular, forming a broad support to the powerful ventral rays. 

 The distance of the vent from the root of the ventral fins exceeds considerably the length 

 of the head. The anterior dorsal ray is inserted above the prseoperculum, and consider- 

 ably longer than the head ; it can be received in a groove on the back. The second 

 dorsal fin commences opposite to the vent ; its anterior portion is triangular in shape, 

 with the longest rays about as high as the body underneath ; a space about as long as 

 the base of the preceding portion follows, and is occupied by a variable number of short 

 and rudimentary rays. These rays gradually increase in length again, and form the 

 posterior portion of the dorsal fin, which, however, is scarcely half as high as the anterior 

 portion, aud terminates at a short distance from the caudal. The anal fin commences 

 and terminates almost opposite to the dorsal, resembling this latter in form and structure, 

 but with a greater number of rays composing the developed portions. The caudal fin is 

 short, with the hind margin slightly excised. 



The pectoral fin is inserted rather high up the sides, and strongly asymmetrical ; it 

 is many-rayed, the rays being inserted on a long and broad base. 



The ventral fins (a) exhibit a very extraordinary structure, and seem to be as much 

 organs of touch as of locomotion. Each fin is composed of five or six rays, of which the 

 three outer ones are enlarged, much prolonged, bearing a dilatation along each edge {a', 

 enlarged), and terminating in fine points. The two outermost rays arc quite free, the 



(ZOOL. CHALL. EXP. — PAKT Lxxvm. — 1S89.) liii 4 



