284 DEEP SEA FISHES. 



cephalidae, and similar fishes, dwell in water that is lighted, perhaps by 

 chemical changes taking place in the ooze on the ocean floor, changes that 

 may at once cause the phosphorescence, retard the waste of tissues, and pos- 

 sibly add something to the supply of oxygen. 



Of the Alepocephalidae, properly so called, a single species was known 

 previous to 1877. The collections of the British steamer '' Challenger " dis- 

 covered six new species, representing among them three new genera. 

 Various expeditions of the United States Coast Survey and the U. S. Fish 

 Commission brought to light nine other species. The work of the Indian 

 government steamer " Investigator " secured eight more, including a repre- 

 sentative of a new genus. The French steamers " Travailleur " and " Talis- 

 man" found six new ones, one of them representing a genus previously 

 unknown. And the present collection by the " Albatross " contains eight 

 species as yet undescribed, one of them adding a new genus to what are 

 already on the lists, another representing a very distinct species of the genus 

 Narcetes discovered by the " Investigator " off the Goa coast. 



ALEPOCEPHALID.E. 

 Leptochilichthys gen. n. 



Body elongate, compressed, well rounded above and below, covered 

 with scales ; body cavity long ; head long, rather broad, deeper than wide, 

 scaleless. Mouth wide ; maxillary and intermaxillary both expanded, deep, 

 thin, sharp on their lower edges. Teeth small, in single series, on mandi- 

 bles, palatines and vomer. Gills four; lamellfB short; gill rakers numerous, 

 leathery ; gill membranes not united, free from the isthmus. Pseudobran- 

 chiae present. Branchiostegal rays numerous. Eyes large, lateral. Dorsal 

 and anal behind the middle of the total length. No adipose fin. Pectorals 

 small, situated low on the side. Ventrals small, forward of the dorsal, 

 Caudal deep, forked. Scales cycloid, smaller on the lateral line. Lateral 

 line very distinct. Pyloric creca few. 



This genus is readily separated from Bathytroctes, which it resembles 

 in position of fins, grooved skull, and other features, by the expanded and 

 toothless intermaxillary, and the number of branchiostegals. The expan- 

 sion to be noticed in the hinder half of the maxillaries of Alepocephalus is 

 in the present genus continued forward on both maxillary and intermaxil- 



