612 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The branchioste'gal membranes form a wide free fold across isthmus. Outer gill-slit wide, about 
two-thirds of orbital diameter. Pseudobranchiae present, very short. Origins of first dorsal, pec- 
torals and ventrals in the same vertical; second dorsal spine finely serrulate throughout, except 
for a very short distance at base and tip; tip not filamentous and fails to reach origin of second 
dorsal; length of spine contained 1.4 in the head; interval between dorsals contains length of 
base of first dorsal 2 to 2.33 times; second dorsal is very low and inconspicuous throughout; anal 
rather high, its origin under last rays of first dorsal; vent well forward, between basal portions 
of inner ventral rays, separated by a band of scales from a round, scaleless depression, which 
lies between middle of bases of ventral fins; distance from anal origin to base of outer ventral 
ray contained 3.25 times in head; outer ventral ray not produced, 2.6 in head; pectoral 1.5. 
Scale small, very rough and adherent, higher than wide, covered with numerous rather long, thick-set 
spines arranged quincuncially; spines on head much shorter; scales covering margins of shoulder 
girdle perfectly smooth; entire snout, suborbitals, and mandibles scaled, the latter with several series; 
lateral line very conspicuous, rising anteriorly in a weak, convex curve. 
. General color dark brownish, breast, belly, and lower side of head blue-black; opercles and posterior 
part of cheeks dusky; fins all dusky, a black line along base of anterior portion of anal fin; basal 
portion of pectorals and axil black. Mouth whitish or yellowish anteriorly, posterior portion of roof 
and the branchial arches black; lining of anterior outer portion of gill cavity whitish, posterior portion 
of gill membranes black; lining of shoulder girdle dark brown. Peritoneum dusky. 
The specimens, nine in number, are all from Sagami Bay, near Misaki, taken on long lines by 
Kuma Aoki; two dredged by the Albatross at station 3695, Sagami Bay. 
(Misaki, red point, a headland at the mouth of the bay of Sagami, famous for zoological work.) 
HYMENOCEPHALUS Giglioli. 
Hymenocephalus Giglioli, Pelagos, Genoa, 228, 1884 ( italicus ). 
Mystaconurus Gunther, Deep Sea Fishes, Challenger, 1887, p. 124 ( longibarbis ). 
This genus is closely allied to Coryphsmoides, differing in the smooth dorsal spine and membrana- 
ceous skull. First dorsal broad, placed far forward over base of pectoral; second dorsal and anal 
origins nearly opposite, and separated by a considerable space from the vertical from end of first 
dorsal; vent far from ventrals. Head large, naked, soft, and cavernous; snout abrupt, perpendicular, 
or parabolic; mouth lateral, wide. Eye very large, orbital margin forming part of profile of head. 
Barbel long. Pectoral rather narrow (10 to 16 rays). Scales thin, deciduous, with fine, short spines. 
Under parts in advance of ventral, wholly or partly naked. Small fishes, remarkable for the papery 
structure of the bones of the head, (vjuf/v, membrane; KecpaXi), head.) 
a. Barbel small and slender, but evident. 
b. Head 5.33 in length; depth 7.25; sides of isthmus striate striatissimus, 96 
bb. Head 6 in length; depth 7.5; dorsal spine slender, not filamentous papyraceus , 97 
aa. Barbel obsolete; head 5.4 in length; depths; dorsal spine slender Iclhonemus, 98 
96. Hymenocephalus striatissimus Jordan & Gilbert, new species. 
Type 108 mm. long, from station 3738, Suruga Bay; depth, 167 fathoms. No. 50934, U. S. Nat. Mus. 
This species seems most nearly related to II. longibarbis Gunther, from the vicinity of the Fiji 
Islands, having a well -developed barbel, only 8 ventral rays, and 8 soft dorsal rays, as in that 
species. It differs from longibarbis in its shorter, higher head and blunter snout, in its much wider 
interorbital space, wider dentate preoperculum, and shorter barbel. The pair of lens-like spots on 
mid-ventral line and the minute striation of sides of isthmus are not described in brevibarbis, but are 
probably present as in all other species of the genus. 
First dorsal ii, 8 to ii, 10; ventral 8; head 5.33 in total; depth 7.25; branchiostegals 7, the 
fourth much widened toward base. 
In form most closely resembling//, ant/rseus, from the Hawaiian Islands. Head large, subquadrate 
in cross section, the short, bluntly rounded snout not ending in a sharp point and not protruding 
beyond the premaxillaries; orbital rims greatly expanded, the median rostral ridge not greatly pro- 
jecting above general level of interorbital space. As in other species the crests are all thin and papery 
and the membranes roofing the canals extremely delicate and easily ruptured. Eye large, circular as 
in antrseus, its diameter two-fifths the length of head; interorbital width one-third of head; length of 
snout 4.1. The middle of length of head lies immediately in front of hinder margin of pupil. 
