Brotulids Killed by 1950 Eruption' — Gosline 
79 
from flap above opercle about to below dorsal 
origin. Scales of sides of body with more or 
less randomly scattered pores, some along 
mid-sides perhaps representing rudiments of 
a lower lateral line. 
Top of head scaled to in front of eyes; 
rami of lower jaw, branchiostegal membranes, 
and maxillary partially scaled; snout in front, 
lips, lower border of suborbitals, and isthmus 
completely scaleless. Snout rim bordered by 
three or four fleshy, leaf-like flaps on either 
side. Six hair-like lines running backward over 
scaleless area of snout on each side, forming 
slight fleshy ridges. No crests or spines on 
head except for a single, weak opercular spine. 
Posterior nostril well ahead of eye, about 
midway between anterior orbital rim and an- 
terior nostril, which exits from a tube well 
back from snout rim. 
Small, granular, pavement-like teeth in 
short, broad, continuous bands on premaxil- 
laries, mandibles, and vomer. Tongue rela- 
tively elongate and pointed but not reaching 
as far forward as vomer. Two developed gill 
rakers below and a third at angle of first arch. 
Pseudobranch reduced to two small filaments 
on one side and one on the other. 
Pelvic fins composed of two filaments each, 
these divided nearly to their base and origin- 
ating below the opercle, the outer about half 
the length of the inner. Pectoral apparently 
short and rounded, undivided, a scaly basal 
lobe extending out about two fifths the length 
of the fin. No sharp point on cleithrum above 
pectoral base. Dorsal commencing about two 
thirds of the way out along the depressed 
pectoral fin. Dorsal, anal, and caudal scaled 
basally. 
Judging from Norman’s key (1939: 80-84), 
Volcanus is most closely related to Luciohrotula 
Smith and Radcliffe (Radcliffe, 1913: 170). 
It differs, however, in lacking a lower oper- 
cular spine, in having an incomplete lateral 
line which is developed as a fleshy tube be- 
tween and above the scales, and apparently 
in the peculiar arrangement of flaps and lines 
on front of snout. Upper part of suborbitals 
and area between posterior nostril and eye 
apparently unsealed in Luciohrotula, but scaled 
in Volcanus. 
Volcanus also bears a superficial resemblance 
to Bassogigas and Neohythites but differs at once 
from these genera in the fewer developed gill 
rakers and the less complete squamation of 
the head. 
Volcanus is named for Vulcan, the Latin 
fire god, to whom I am much indebted for 
sending this fine fish collection. 
Volcanus lineatus n. sp. 
Tables 1, 2; Figs. 2d, 3V 
holotype: U. S. N. M. 162716, a female 
267 mm. in standard length, collected by 
Moore et al., June 3, 1950, off the Mauna 
Loa lava flow, Hawaii. 
The holotype at present has the head thrown 
back and the gill covers widely flaring. It is 
more or less impossible to judge the head 
shape in life. However, the head appears to 
be relatively small, its length about equal to 
its distance from the anus. The eyes seem to 
be on the dorsolateral surface of the head and 
are separated by a flat interorbital. The pos- 
terior nostril is a semicircular hole with the 
median rim straight. Just posteromedially of 
this nostril a narrow, linear fleshy ridge com- 
mences (resembling a thin barbel attached to 
the surface of the head for its entire length) 
which runs back along the upper rim of the 
orbit. There are four or five scale rows en- 
circling the eye below and in front, except 
for the area of this ridge. Scaleless area of front 
of snout with other, similar, longitudinal 
ridges. Rim of snout with small, overlapping, 
leaf-like appendages. Maxillary reaching about 
half an eye diameter beyond eye, with a sm'all 
patch of about six scales posteriorly. Sub- 
orbital rim double for most of its length, with 
about three inconspicuous pores along its 
lower edge. Mandibles covered below by a 
series of assorted scales, fleshy ridges similar 
to those on front of snout, pores, and pockets 
with papillae in center. Top of head poste- 
riorly, and to some extent the cheeks, with 
