PHILIPPINE MACROUROID FISHES—GILBERT AND HUBBS. 537 
the sensory canal system and thin bony septa of the head are devel- 
oped, this species holds a position intermediate between striatissimus 
and its allies on the one hand, and longiceps and longipes on the 
other. The gill-membranes, which are free from the sides of the 
isthmus, unite, with a free fold, below the posterior margin of the 
orbit. The gill-rakers are arranged as in other species of the sub- 
genus Hymenocephalus, there are two series of 18 on the lower limb 
of the outer arch; those of the outer series are decidedly more 
crowded and smaller than those of the inner series, as they are con- 
fined to the restricted limits of the first gill-slit, which is only about 
as long as the orbit. Seven branchiostegals. 
The distance between the anus and the ventral base is equal to the 
distance from the tip of the snout to the hind margin of the orbit, 
Fic. 33.—HYMENOCEPHALUS NASCENS. TYPE. 
and about equal to the distance between the ventral base and the fold 
of the gill-membranes across the isthmus. 
The ventral lens-shaped organs are both round; the diameter of the 
posterior of the two, although about twice that of the anterior one, is 
but one-fourth that of the pupil (half pupil in dongiceps and longipes). 
The few large scales retained on the side of the type bear 10 to 16 
fine sharp spinules, directed backward, and arranged in quincunx 
order. The lateral line is rather poorly developed; it is separated 
from the first dorsal base by 2 rows of scales and from the front of 
the second dorsal by 4 rows. 
No denticulations on the second dorsal spine are apparent. The 
length of the first dorsal base is contained 1.9 (1.5 to 2.1) times in 
the interval between the dorsal fins, and 1.2 (1.2 to 1.3) times in the 
postorbital length of the head. The length of the weak and slender 
pectoral fin is contained 1.6 (1.6 to 1.9) times in the head; the outer 
ventral ray, with its filament, 1.25 (1.1 to 1.3) times; the second 
ventral ray, 2.1 (2.0 to 2.35) times, barely reaching to the anus. 
