DIBRANCHICHTHYS NUDIV0MP:R. 



99 



The differences between young and old in this species indicate that the 

 species has been derived Irom one with a pointed snout and hirger tubercles. 

 The appearance is that of a more degenerate form than any o£ those in the 

 collection from much greater depths. 



DiBRANcnicnTHYS gen. n. 



Head and body depi-essed, together forming a broad rounded disk ; cau- 

 dal region distinct, slender, tapering. Rostrum excavated below in a recess 

 lodging a trilobed protractile illicium. Nostrils and mouth anterior ; latter 

 transverse, oblique. Teeth absent from the vomer, present in villiform 

 groups or bands on palatines, jaws, and tongue. Eyes large, with horizontal 

 outlook. Gills two, none on first and fourth arches ; gill openings small, 

 placed supei'iorly in the axillte ; no pseudobranchia3. Fins small, of few 

 rays ; anal narrow, backward of the dorsal. Skin above and beneath covei'ed 

 with unequal broad based spines or tubercles. 



In a general way this type is similar to Halieutfea and especially so to 

 Dibranchus or Malthopsis. The discovery of this form is suggestive of a 

 possible degradation of a number of closely allied genera to the rank of sub- 

 genera in a revision of the family. 



Dibranchichthys nudlvomer sp. n. 



Br. r. 6 ; D. 6 ; A. 4 ; V. 5 ; P. 13 ; C. 9. 



In the regularity of its outlines this species approaches McdtJiopsis erina- 

 cea ; it is easily distinguished by being more oblong, having a shorter ros- 

 trum, and by the weakness of the subopercular tubercle besides the more 

 important feature, the absence of vomerine teeth. Body and head greatly 

 depressed, together forming a disk in which the length or the width of the 

 head is about seven eighths of the length of the body ; tail elongate, narrow, 

 round, tapering from the vent. Crown slightly arched. Snout short, 

 blunt, concave on the top, with a low ridge forward from the orbit and a 



