350 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 
e’, Gill-rakers 6+17; eye half length of snout or of interorbital 
SPCC wos hase S Se ee eee cee cottoides. 
e*. Gill-rakers 5 or 6+19 to 22; eve more than half length of snout 
or of. interorbitale Spa Ces a= = ee ne spongiceps. 
d°’. Insertion of ventral fins below that of pectorals; distance from 
anus to base of ventral equal to the postorbital length of the head; 
Color. Uiglity 23 se ae lee favosus. 
b*. First dorsal, pectoral and ventral fins each with a filamentous ray 
longer than the head; color lighter than in B. bowersi or B. cot- 
loides =. > oe fy Ne eta ne ee ee antrodes. 
a*, Orbit more than two-thirds interorbital width (orbit 1.4 to 1.6 in inter- 
orbital in B. filamentosus) ; head only moderately wide and cavernous; 
seales on mandible in 14 or 2 series_______________ (MELANOBRANCHUS). 
f*. First dorsal, pectoral and ventral fins each with a filamentous 
ray longer than the head. 
yg. Barbel not present; orbit 1.4 to 1.6 in interorbital width; 
about 20 gill-rakers on lower limb of outer arch_filamentosus. 
g’. Barbel small, but evident; orbit 1.0 in interorbital width; 35 
gill-rakers on lower limb of outer aoe iS, Oi ae micronema. 
P: ae without long filaments. 
. Barbel absent, 
a4 Ventral with 10 rays; 19 gill-rakers on lower limb of outer 
arch; pseudobranchiae present; interorbital little wider 
than orbit, 3.7 in head; snout scarcely longer than orbit ; 
branchialccavity swhollyoblack== === = sss entomelas. 
i. Ventral with 8 or 9 rays. 
7. Orbit shorter than snout. 
k*. 19 to 21 gill-rakers on lower limb of outer arch; 
pseudobranchiae present in adult; interorbital 4 in 
head; branchial cavity wholly black____furvescens. 
k*. 16 gill-rakers on lower limp of outer arch; pseudo- 
branchiae absent in adult; interorbital 3.43 in head; 
coler much lignter, the posterior margins of the 
opercular and gill membranes irregularly lighter or 
WV TET SES So a nipponicus. 
. Orbit decidedly longer than snout, about equal to inter- 
OEDIEA Wid thts ss seo Sait 2 2 Ne eee melanobranchus. 
h*, A small barbel present. 
E“interorbitale wider than) cy ess == eee garretti. 
lV’. Interorbital much narrower than eye. 
m, Tonner shagreen-like portion of premaxillary band 
of teeth forming only a narrow border to the 
band; orbit 4 in head; ground color chocolate ; 
iris dark; ventrals with 9 rays; barbel tuber- 
Gulla’ So 2... * 2 ee eS ee ee sulcatus. 
nm’. Inner shagreen-like portion of premaxillary band 
of teeth about half as wide as the entire band; 
orbit very large, 23 to 3 in head; ground color 
silvery or gray, including iris; ventrals with 8 
rays: barbel’slenders2 2422 es macrops * 
Amore Be species on Satnuiaiun B. macrops most closely approaches the genus 
Gadomus as defined by us. 
