180 DEEP SEA FISHES. 



them all lie between 37.3 and 40 degrees Fahrenheit, averaging about 38.8 

 degrees. The variation in the temperatures of the different stations is 

 remarkably small but that in the pressures at the widely different depths 

 is enormous. 



GADID.E. 



MiCROLEPiDiUM gen. n. 



Form more comjDressed, deeper and more massive in the forward half 

 than that of Lepidion, tapering to very slender backward ; body cavity less 

 than half of the total ; body and head covered with small scales. Mouth 

 large, oblique, lower jaw longer. Teeth in villiform bands on the jaws, 

 stronger and in a V-shaped single series on the vomer, none on the palatines. 

 Eyes large, lateral. Branchiostegal rays seven. Gills four, a slit behind 

 the fourth ; rakers numerous, long, slender. Gill openings wide ; membranes 

 united, free from the isthmus. Pseudobranchiaj present. No barbel. Two 

 dorsal fins ; anterior small, of eight rays. One anal fin ; caudal narrow, 

 distinct ; pectorals small, elongate ; ventrals long, narrow, apparently of a 

 single bifid ray, but really of two raj'S closely bound together and with 

 rudiments of a couple of others. Pyloric casca. 



Microlepidium differs from Lepidion in having the lower jaw longer than 

 the upper, in having a longer first dorsal of eight rays instead of four, in 

 having the dorsals hardly separated, in having ventrals of four rays instead 

 of six, in having a less distinct latei'al line, and in having a much larger 

 number of pyloric appendages. 



Of the two known species of this genus, one, M. rerecundum, Lejyidion verc- 

 cundum, Gilb., 1896, P. U. S. Mus., 456, has the maxillary reaching to below 

 the front of the pupil, " astiffish pointed projection representing the barbel " 

 on the end of the lower jaw, no spines on snout or opercles, ventrals half as 

 long and pectorals about half as long as the head, an anal of thirty-seven rays 

 and deeply notched behind the middle, and has about seventy-five scales in a 

 longitudinal series ; while tliat described below has the maxillary subtending 

 more than half of the eye, has no projection on the chin, has a moderately 

 strong spine on the operculum, has ventrals a little longer than the head, 

 has pectorals more than two-thirds as long as the head, has on anal of forty 

 rays hardly notched near the middle, and has about one hundred and four- 

 teen scales in a longitudinal series. M. verccundmn was obtained by the 

 "Albatross," near the Revilla Gigedos, off the Coast of Mexico, in a depth 

 of 364 fiithoma 



