PHILIPPINE MACROUROID FISHES—GILBERT AND HUBBS. 521 
k*. Striations behind ventral fins much finer than those above 
ventrals or on isthmus; form more slender______ italicus. 
k*. Striations behind ventral fins not finer than those above 
ventrals or on the isthmus; form more robust___---_- 
CaVvErnosus. 
j. Barbel minute or obsolete; no striated areas directly below 
pectoral bases nor in front of ventral bases; compared 
with cavernosus, the ventral lens-like bodies are smaller, the 
eolor is darker, and the bands of teeth are narrower____ 
antraeus.* 
?. Snout about as long as the interorbital width, projecting beyond 
mouth, pointed; barbel wholly absent, or rudimentary. 
I’. Color lighter, grayish along bands of teeth in jaws. 
m*. Ventral rays usually 11, sometimes 12________ lethonemus. 
m*, Ventral rays usually 12, sometimes 11 or 13______ NaScens. 
?. Color darker, black along bands of teeth in jaws; ventral 
TAY S eile LOL yet aid oe a ee ee striatulus. 
iW’. Bye 3% in head, § interorbital width; snout % eye; barbel dis- 
tinctly developed; ventral rays 10 to 12 (readily separable on 
account of its small orbit from H. italicus and H. cavernosus, 
the only species in the subgenus with which it agrees in the 
number of ventral rays and the development of the bar- 
LB) emi ES eh ae ie ae ee ee eae ae ek a aa Se heterolepis. 
A‘. Body deeper; sensory canals of head excessively developed, as in the typical 
subgenus of Bathygadus; bony septa of skull exceedingly thin and 
papery ; eye small, 4 to 5 in head; color chiefly blackish. 
PAPYROCEPHALUS. 
a. Barbel present, very small. 
GeV ETAL SUE AT ANY Sn een eats wie eles eS at Beh ee Se a barbatulus. 
PeaVCTEE Mesa st tleweas oe eas Ra a eae Sg papyraceus. 
io barbelLcdbsent= VEntralsrays tenor Paes = ck aterrimus. 
HYMENOGADUS, new subgenus. 
Ty pe-species —Hymenocephalus gracilis, new species. 
This subgenus is erected to include two closely related species— 
the type-species and 77. tenuis*—which we have recently described 
from the Hawaiian Islands. The two species are closely related, and 
differ strikingly from all other known species in the denticulation of 
the dorsal spine, in the reduced gill-rakers, and in the cylindrical 
form of the head. Their reference to Zymenocephalus is made be- 
cause of their agreement with the other species of the genus in the 
possession of certain diagnostic characters conservatively retained 
throughout the group. Among these characters the most prominent 
are: the forward extension of the branchial aperture; * the compara- 
tively wide slit before the first gill-arch; the “striation” of the 
abdominal region; the presence of two lens-like bodies in constant 
1 Specimens of this Hawaiian species from Albatross station 3467 have never been 
recorded. 
2 Gilbert and Hubbs, Proc. U. S. Nat. Mus., vol. 54, 1917, p. 173. 
In this character Hymenocephalus is approached by two other genera, Malacocephalus 
and Ventrifossa. 
