EEPORT ON THE DEEP-SEA FISHES. 231 



The form of the body of this extremely interesting type is compressed and elongate, 

 in fact it simulates in some respects the Stomiatid type. The depth of its body is nearly 

 uniform between the head and vent, and contained six and a half times in the total 

 length (without caudal) ; the length of the head, which is compressed and much longer 

 than deep, five times and one-third. The length of the upper surface of the head only 

 half the length of its side ; snout extremely short and obtuse, with its anterior profile 

 parabolic. Mouth small, provided with extremely small teeth on the intermaxillary and 

 on the anterior portion of the mandible. The maxillaiy is short, broad, very thin, ex- 

 tending somewhat bej^ond the anterior margin of the eye. Eye well developed, im- 

 mediately below the upper profile, wider than the interorbital space, and tsvo-ninths of 

 the length of the head ; it is much longer than the snout. 



The gill-opening is closed above, and liegins from opposite the root of the pectoral 

 fin. Branchiostegals slender, six in number. Four gills, with well-developed laminae ; 

 gill-rakers rather long, stout, lanceolate, twenty-five on the outer branchial arch. The 

 opercles and branchiostegals are enveloped in a common thick skin, so as to be 

 indistinguishable without dissection. 



Vent midway between the roots of the caudal and pectoral. The dorsal fin 

 commences immediately above, and the anal behind the vent ; both fins low, coterminal ; 

 peduncle of the tail not quite twice as long as deep. The caudal fin is deeply forked, 

 each lobe produced into a short filament ; the upper and lower rudimentary rays are 

 numerous and extend forwards for more than one-half of the length of the peduncle. 

 Pectoral fin inserted low down the sides, with a very narrow base, rather pointed behind, 

 and three-fifths of the length of the head. The ventral fins are likewise narrow, half as 

 long as the head and extending to the vent. 



The skin is tough and leathery, finely wrinkled longitudinally, with minute scale-like 

 productions irregularly scattered over the body. The lateral line is a broad continuous 

 straight canal, which arises close behind the eye and runs along the middle of the body 

 and tail. Very small raised nodules ^ with whitish centre are distributed over the body. 

 They are arranged in subquincuncial order, and even extend on to the rays of all the fins 

 except the caudal. On the head they form series, one series following the infraorbital 

 ring, two others the lower limb of the prseoperculum, and the fourth the margin of the 

 gill-opening. I consider these organs to possess luminous properties. 



Fig. c on PI. LVIII. represents a piece of skin slightly magnified, with four 

 luminous nodules and a number of minute scattered scales. 



' Thi.ir liistological structure will be described in Appendix B. 



