96 DEEP SEA FISHES. 
is a considerable amount of individual variation in the number of spines on 
each tubercle; this aside, however, the tubercles are of much assistance in 
the determination of the species of this genus and of allied genera. 
Width of disk equal to the distance from the snout to the gill openings, 
that is, a little less than twice the length from snout to nape. Crown flat- 
tened. Snout short, with a deep naked cavity on the top, hardly pro- 
truding beyond the lower jaws, with a series of five erect tubercles around 
the outer edge, with a strong antrorse tubercle above the inner edge of 
each nasal sac, subrostral area deeply excavated for the trilobed protractile 
illicium, rostrum separated by a very shallow notch from the preorbital 
ridge. Eyes large, length equal to the width of the interorbital space, 
longer than the snout, orbits convergent forward. Mouth medium, width 
about four fifths of the distance from snout to nape. Teeth in villiform 
bands on jaws and tongue, absent from palatines and vomer. Gills two, 
absent from first and fourth arches ; openings small, placed superiorly in 
the axilla. Branchiostegal rays six, outer stronger and joined to the 
opercular bones. Subopercular tubercles strong, with four spines; the 
anterior pair on the stem, one of them directed obliquely outward and 
somewhat upward, the other out and downward; the terminal pair blade- 
like, one of them directed outward, the other in toward the gill opening. 
Spines tubercular, strong, unequal, with sharp cusps and broad striate bases, 
largest on the top and the sides of the tail and along the edges of the disk 
where some have two spines and others three, very small and more separ- 
ated on the lower surfaces. 
Fins small; dorsal origin behind the midlength of the disk; anal origin 
little backward of the end of the base of the dorsal, fin reaching backward 
of the bases of the caudal rays; caudal nearly as long as the skull to the 
nape, somewhat pointed; pectorals medium, less than twice as long as the 
ventrals, fringed. 
Blackish externally and on the linings of the body cavity. 
Station. Latitude. Longitude. Depth. Temperature, Bottom. 
3418 ; 16° 33’ N.; 99° 52’ 30” W.; 660 fathoms ; 39° BF; Br. 8. bk. Sp. 
DIBRANCHOPSIS gen. Nn. 
A Dibranchoid in which the skeleton has degenerated to become semi- 
cartilaginous, in which the subopercular process and spines and those of the 
rostral angle are obsolescent or obsolete, obsolescent in young, obsolete in 
