Fig. 3. a, Diplacanthopoma {rivers-andersoni'^)\ b, Diplacanthopoma (sp.?); c, Cataetyx hawaiiensis; d, Volcanus 
lineatus; e, Pycnocraspedum armatum. Above, tooth bands of upper jaw and roof of mouth; below, tongue and tooth 
bands of lower jaw and on lower half of gill arches. Upper pharyngeals and spinous gill rakers omitted. The 
bases of the gill slits are shown (hatched) in two species. Certain differences in the relative position of the parts, 
e. g., whether or not the gill covers are widely flaring, are undoubtedly caused by differences in preservation. 
ping scales. Eleven caudal rays articulating 
with a single, medianly incised hypural plate. 
Head depressed forward, eyes high on snout 
and directed more superiorly than laterally, 
covered with scales except for isthmus, lips, 
maxillaries, and area around rim of snout. No 
spines on head except for single opercular 
spine. Maxillary extending about half an eye 
diameter beyond eye, largely concealed by 
suborbitals when mouth is closed. Posterior 
nostril a large hole near front of orbit and 
slightly below level of middle of eye. An- 
terior nostril over snout rim. Snout with three 
enlarged pores on either side in front just 
above rim; two pores near lower border of 
suborbitals; a pore on mandibles on either 
side of isthmus under jaw bone; about three 
pores along rami of hyoid arch, and one 
on lower border of preopercle. Free preoper- 
cular border more or less rounded, spineless. 
Opercle not ending in a sharp point below. 
Flap above opercle covered with minute scales. 
Teeth in upper jaw in a villiform band; 
laterally, teeth increase somewhat in size from 
outer to inner row. Mandibular rami raised 
posteriorly, their teeth in long bands. In front 
the mandibular teeth are in about a half 
dozen rows, outer three or four small, inner 
somewhat enlarged. Faterally, teeth in two 
rows, inner consisting of sharply conical teeth 
several times as large as those of outer row. 
Posteriorly, outer row of small teeth drops 
out leaving only a single row of enlarged 
teeth, this row continuing well behind pre- 
maxillary rows. Vomer with two patches of 
teeth separated by a median interspace under 
which the tongue protrudes; each patch con- 
sists of about a dozen slightly curved, conical 
teeth. Palatines with long band of conical 
teeth less than half the size of those on vomer, 
with inner rows larger than outer. No teeth 
on tongue or on bases of the four gill arches. 
