586 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Gavialiceps txniola Wood-Mason, from the Bay of Bengal, has been subsequently referred by 
Alcock to the genus Nettastoma. But as the posterior nostril is “situated laterally nearly midway | . 
between the eye and the tip of the snout,” the gill-openings are “ of moderate size, almost meeting in 
the mid-ventral line;” there is present a fleshy tongue, and the mandible and vomer are abruptly i 
expanded at tip, the species would seem to belong to a genus distinct from Nettastoma, for which the 
name Gavialiceps must be retained. Gavialiceps Wood-Mason, first appears in a paper by Alcock “On i 
the Bathybial Fishes of the Bay of Bengal” in Ann. Mag. Nat. Hist. (6) vol. 4, 1889, p. 460. Two H 
species are described: G. txniola Wood-Mason and G. microps Alcock. There can be no doubt that | 
G. txniola must be considered the type of the genus, and this would become a synonym of Nettastoma I 
if Alcock’s later views are correct, and the characters indicated above are not of sufficient importance 1] 
to warrant generic separation. The immature types of G. txniola are said to have no pectoral fins, j ; 
In later papers, in describing the adults of G. txniola, Alcock neglects to call attention to the presence I j 
of pectoral fins, though their presence would be inferred from his reference of the species to Nettastoma. j 
If they were absent in the types of the species, but were present in the adult specimens subsequently H 
acquired, an error must have been made in the identification of the adults, as pectorals are present I] 
even in the larval stages of eels which possess pectorals in the adult condition. 
For the nemichthyoid genus, without pectoral fins, typified by Gavialiceps microps, to which Alcock II 
erroneously restricts the genus Gavialiceps, I would propose the name Alcockidia, in honor of its ffl 
distinguished discoverer. 
Family NEMICHTHYID^. 
Serrivomer beanii Gill & Ryder. 
Three specimens were obtained, which I am unable to distinguish from Garman’s figure and H 
description of S. sector from the Pacific coast of Mexico and Central America. Garman fails to point L 
out any characters by which S. sector differs from S. beanii of the Atlantic. S. beanii has received no Kj 
description beyond a few trivial remarks, but the figure of the type presented by Goode and Bean Ij 
(Oceanic Ichthyology, 1896, fig. 175) agrees so closely with the Pacific form that I do not venture to I 
separate them. Differences may appear when it is possible to compare material from the various H 
localities. 
The specimens were taken at the following stations: 3910, off the south coast of Oahu, 311 to 337 I 
fathoms; 4157, vicinity of Bird Island, 762 to 1,000 fathoms; 4183, vicinity of Kauai, 957 to 1,067 1 
fathoms. 
Stemonidium, new genus. 
Intermediate in ne respects between the groups typified by Nemichthys and Serrivomer, having Ij 
the dentition of the former, and the short straight jaws, small eyes, long postorbital region, and wide, I 
partly confluent gill-openings of the latter; it agrees with Serrivomer also in the position of the nostrils ■ 
and the absence of the lateral line pores. The pectorals are reduced in size, with few rays, and are I 
very slender. The dorsal originates behind the occiput a distance equal to half the length of the ■ 
head, and the vent is remote from the head. Not closely related to any known genus, but nearer II 
Serrivomer than Nemichthys, in spite of its reduced dentition. 
Stemonidium Gilbert, new genus of Nemichthyidse (hypomelas). 
Stemonidium hypomelas, new species. Plate 67. 
Typef 171 mm. long, from station 4176, vicinity of Niihau Island, depth 537 to 672 fathoms; type, I 
No. 51550, U. S. Nat. Mus. 
Head 17 hundredths of the total length; distance from tip of snout to front of anal 26; from tip of I 
snout to front of dorsal 25; from tip of snout to front of eye 8; diameter of eye 1; length of pectoral I 
1.5; greatest depth of body 3; interorbital width two-thirds diameter of eye. 
Body narrowly band-shaped, of nearly uniform depth in its middle half, tapering to the narrower 
neck, and rather rapidly to the pointed but short and not filamentous tail; eye very small, in the middle I! 
of length of head, one-eighth the postorbital length of head, a little longer than interorbital width; 
head and beak shaped much as in Serrivomer; upper profile descending in a straight line from occiput | 
