146 DEEP SEA FISHES. 



BROTULID^. 

 Leucicoeus gen. n. 



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 villil'orm bands, on jaws, 

 vomer, and palatines. Skeleton firm. Muciferous cavities highly developed 

 on. the skull. J^ye peculiar, eyeball rudimentary, obsolescent, no iris nor 

 pnpil 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. Pseudobranchiaj rudimentary. Brancbiostegal rays 

 eight. Tongue margins free. Vertical fins confluent ; caudal narrow ; ven- 

 trals small, close together, at the luimeral symphysis, each composed of two 

 rays bound together. No pyloric appendnges. 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 pseudobranchiae, the rudimentary eyes, and 

 the extraordinary development of the mucous system. 



Leucicorus lusciosus sp. n. 

 Flafe XXXVIII. ; Tlate LXXIV. fig. 1, Lai. Sij^t. 



Br. r. 8 : D. 110-119 ; A. 95-101 ; V. 2 ; P. 24 ; LI. ca. 148 ; Ltr. ca. 35. 



Compressed and elongate in form, depth near one seventh of the total 

 length. Head medium, near oue fifth of the total, nearly as broad as deep. 

 Snout broad, somewhat prominent in the iuternarial 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 stu'i'ace 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 diffei-S 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 frou) 



