146 DEEP SEA FISHES. 
BROTULID A. 
LEUCICORUS gen. Nn. 
Myxoniform, elongate, slender, compressed, covered by scales on body 
and head. Head medium, short, rounded; snout broad, blunt; mouth wide, 
anterior ; jaws nearly equal. ‘Teeth small, in villiform bands, on jaws, 
vomer, and palatines. Skeleton firm. Muciferous cavities highly developed 
on the skull. Eye peculiar, eyeball rudimentary, obsolescent, no iris nor 
pupil apparent, no orbital fold. Hinder nostrils far apart, close in front of 
the eyes; anterior half way from the posterior to the edge of the lips. A 
median keel on the top of the snout, another at the occiput. An opercular 
spine. A short slit behind the fourth gill. Gill filaments short. Gill rakers 
slender, numerous. Pseudobranchiz rudimentary. Branchiostegal rays 
eight. Tongue margins free. Vertical fins confluent ; caudal narrow ; ven-_ 
trals small, close together, at the humeral symphysis, each composed of two 
rays bound together. No pyloric appendages. Pectorals simple. 
This genus is closely allied to Mixonus but differs in the simple pec- 
torals, in which the lower rays are weaker and united by membrane to 
the upper, in the rudimentary pseudobranchix, the rudimentary eyes, and 
the extraordinary development of the mucous system. 
Leucicorus lusciosus sp. n. 
Plate XXXVI. ; Plate LXXIV. fig. 1, Lat. Syst. 
Br. r.8; D. 110-119; A. 95-101; V.2; P. 24; Li. ca. 148; Lth ca. 35. 
Compressed and elongate in form, depth near one seventh of the total 
length. Head medium, near one fifth of the total, nearly as broad as deep. 
Snout broad, somewhat prominent in the internarial region, longer than 
the eye, about two thirds as deep as broad. Crown slightly convex, with 
a thin skin and very thin transparent scales over the mucous cavities, which 
extend over the entire upper surface and are probably light producers. 
Orbit lateral, upper edge bony, strong, prominent; no orbital fold. Eye 
rudimentary, apparently without pupil or iris, and with the ball greatly 
reduced and covered with black pigment. The eye differs greatly in 
appearance from that of other species of Brotuloids and suggests a possible 
adaptation to sensation from phosphorescence, or perhaps a modification 
fitted for the production of phosphorescent light. Posterior nostrils widely 
separated, in front of the eyes and close to them; anterior half way from 
