DISCUSSION OF SPECIES AND THEIR DISTRHU'TION. 43 



Eadial fornmla: B. 7; D. KJ; A. 17; V. 8; L. lat. ca. 70. 



Oue specimen, 10 iuclies long, was taken by the ChalleiKjcr, southeast of Cape St. Vin- 

 cent (Station V), at a depth of 1,090 fathoms, and another by the Investigator, in the Anda- 

 man Sea, SOOfathoms. 



BATHYTEOCTES MELANOCEPHALUS, Vaillant. 

 Bathijlroctes melanocephalus, Vaillant, Exp. Sci. TravailleTir et Talisman, 1888, 15."!, j)!. xi. figs. 3a, 3b. 



Height of body one-fiftli of total length, its greatest thickness one-eighth. The length 

 of the head is two-fifths of the total lenj;th; the anterior ])r()file is somewliat olilicjue. The 

 length of the snout is equal to one-third of the distance from its tip to the posterior edge of 

 the operculum. The maxillary extends to a vertical slightly behind the posterior margin of 

 the orbit. The intermaxillary teeth and those on the mandible are elongate, fine, conical, 

 uuiserial, separated from each other by spaces scarcely equal to their own thickness. The 

 eye is very large; its diameter two-elevenths of the length of the head; interorbital .space 

 slightly less. In fresh condition the ftamework on the operculum, which is very delicate, 

 is hidden in the soft integument, forming a curtain, far extended posteriorly. After having 

 been in alcohol, a great number of radiating ribs, extending downward and backward on 

 the operculum, are seen. Vent considerably in advance of the anal, and near the middle of 

 the distance from the posterior edge of the o]ierculum to the base of the caudal. Lateral 

 line is in the median line of the body, except in its anterior part; the scales which compose 

 it are more conspicuous than on the rest of the body — twice as large, that is to say, one 

 of them corresponds ordinarily to two transverse rows — and there are about 64 of them in 

 the total length of the lateral line. The dorsal is inserted above the interspace between the 

 ventrals and the origin of the anal, the anal being shorter than the dorsal. Both anal and 

 dorsal are low. Caudal emarginate. Pectoral and ventral short, the former with 13 rays. 



The body is grayish green; head deep, blackish blue; fins brown; eye with gray blue 

 iris and black pupil. Scales oval, those of the lateral line peculiar in form (fully described 

 and figured by Vaillant). 



Four specimens were obtained by the Travqillenr in the middle eastern Atlantic; two 

 from the coast of Morocco, from 2,L'00 to 2,.500 meters; one from the coast of Soudan, 1,435 

 meters; one from the Banc D'Arg-uin, 1,670 meters. The type is 108 millimeters in length. 



It would appear from the published descriptions that B. melanocephalus is well distin- 

 guished from J!, microlcxiis, although both have been taken in the same region. The most 

 salient diagnostic characters, as published, are included in the analytical key to the species 

 on a preceding page. 



BATHYTROCTES (TALISMANIA) HOMOPTERUS, (Vaillant.) 

 Balhyirocles homoptcriis, Vaillant, Exp. Sol. Travailhnir ot Talisman, 1888, 153, pi. xii, fig. 1. 



Body elongate; its height one-seventh of its total length; thickness one-thirteenth. 



The length of the head is about one-third of the total length, and the snout one-third 

 of the length of the head. The maxillary extends nearly to the vertical fi-om the middle of 

 the eye, and, like the intermaxillary, it is armed with conical teeth, not very closely set. 

 Teeth on the mandible lancet-shaped, curved inward. Opercular apparatus membranous. 

 Vent twice as far from the snout as from the root of the caudal. The dorsal and anal fins 

 are nearly opposite and approximately equal in length (the type specimen was much muti- 

 lated, and an exact description has not been given); the origin of the dorsal is above the 

 vent, and the length of its base is slightly greater than the greatest height of the body; 

 the anal resembles it very closely and extends very slightly beyond it posteriorly. The 

 pectoral fin appears to have been somewhat elongate, pointed, with its tip extending beyond 

 the base of the ventral, which is situated almost in the middle of the length of the body. 

 Scales moderate, above and 14 below the lateral line. 



Eadial formula: D. 19; A. 19+ ; B. 9; L. lat. 64. 



