LEPTOCHILICHTHYS AGASSIZIL 285 



lary. It appears much as if the shght expansions, on tlie intermaxillary, 

 figured on Plate LXVIII. fig. 2", of Buthi/trodes alvifrons, obtaining also on 

 B. rostra/us 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 witli the Alepocephalida3. 

 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. 



Leptochilichtliys Agassizii sp. n. 



Fla/e L VIIL fig. 3 



Br. r. 13 ; D. 14 ; A. 13 ; V. 10 : P. 11 ; LI. 57 ; Ltr. 6 + 1 + 8. 



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 

 length 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- 

 maxillaiy 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; lamince short, narrow; gill rakers 8+ 19, 

 broad, thin, leathery, rounded to a point, with a row of small tooth-like 



