LEPTOCHILICHTHYS AGASSIZII. 285 
lary. It appears much as if the slight expansions, on the intermaxillary, 
figured on Plate LXVIII. fig. 2*, of Bathytroctes alifrons, obtaining also on 
B. rostratus and others, were in Leptochilichthys carried to a much greater 
development and turned downward to form the cutting edges. Superficially 
the upper jaws bear some resemblance to those of some Clupeoids, but the 
affinities of greatest importance connect the genus with the Alepocephalide. 
Differing so much from all the members of the family it might be well to 
set it apart in a separate division, characterized by the expanded and 
toothless intermaxillaries and maxillaries, the thirteen branchiostegal rays, 
etc. 
Leptochilichthys Agassizii sp. n. 
Plate LVII. fig. 3. 
Brearley le AS: - Vel). Bailie TBR oii saiitreG vl St 
Upper and lower outlines of the body, without the fins, somewhat similar 
and regular in their curves; depth more than one sixth of the total length. 
Head about one third of the entire length, twice as long and three fifths as 
wide as deep, widest at the occiput, cheeks somewhat concave, crown with 
a deep and wide longitudinal groove between strong ridges from occiput to 
nostrils. Snout longer than the eye, deep, blunt, thick, rounded, upper and 
lower outlines much alike in curvature. Eye large, lateral, one sixth of the 
lengtb of the head, two thirds as long as the snout, as wide as the inter- 
orbital space. Mouth very wide, more than half the head length ; maxillary 
long, extending backward one orbital diameter farther back than the orbit, 
compressed and bladelike nearly its entire length, rounded and bearing a 
small angular extremity backward, with a moderate supramaxillary bone 
upon the hinder portion, with a longitudinal keel along the outside ; inter- 
maxillary short, less than half as long as the maxillary, like the latter blade- 
like and sharp edged at the mouth. Both maxillary and intermaxillary are 
broadened like the posterior section of the maxillary of Alepocephalus. 
These broad blades extend downward outside of the mandibles and give 
the mouth a swollen appearance. Protuberance below the angular moder- 
ately developed. Teeth very small, in single series on dentaries and 
palatines, in a series of about five stronger ones on each side of the vomer, 
Upper jaws apparently toothless. Gill openings very wide; membranes 
not united, free from the isthmus; lamine short, narrow; gill rakers 8 + 19, 
broad, thin, leathery, rounded to a point, with a row of small tooth-like 
