360 
setae are pinnate. In a figure titled "Caudal Ap- 
pendage" drawn by Utinomi (loc. cit., text fig. 
4E ) , a portion of the first article of the peduncle 
of the sixth cirrus is illustrated. Utinomi figures 
two rows of conspicuous small, stout barbs (it 
is possible that the two-row effect is produced 
by an approaching molt), and a major simple 
spine of the caudal appendage. The present 
species has but a single inconspicuous row of 
smaller, less numerous barbs and these occur 
on the pedicles of all cirri. The major spines of 
the caudal appendage are densely and con- 
spicuously plumose, an unusual feature, one ap- 
parently lacking in M. striatum. Finally, the 
outer surface of the pedicles of all cirri are 
transversely marked by fine, closely spaced lines. 
Me galas ma ( Megalasma ) striatum is reported 
from the spines of sea urchins from deep waters 
of the Indo-Pacific and Japan, while the species 
described here is so far known only from gor- 
gonacean skeletons in the eastern Pacific, nearly 
9000 miles from the known range of M. (M.) 
striatum. 
family HETERALEPADIDAE 
Nilsson-Cantell 
Synonymy. Nilsson-Cantell, 1921. 
GENUS Heteralepas Pilsbry 
Heteralepas mystacophora Newman, sp. nov. 
Figs. 3 A-H 
DIAGNOSIS: Capitulum ovoid, slightly com- 
pressed, lacking valves; cuticle smooth, with or 
without indistinct carinal ridge; orifice one- 
fourth length of capitulum; lips protuberant, 
margins crenulate; position of scuta marked by 
slightly elevated oval thickenings below and to 
either side of the orifice; peduncle approximately 
one-half length of and distinct from capitulum; 
cuticle smooth, marked by fine lines; peduncle 
expanded into attachment disc; labrum slightly 
bullate, bearing a remarkable growth of fine, 
soft setae; crest toothed; lateral portions squa- 
mous; mandible with four teeth, including in- 
ferior angle; superior margins of second and 
third teeth supporting several widely spaced 
spinules; first maxilla with three major spines 
above and approximately seven major spines 
PACIFIC SCIENCE, Vol. XVIII, October 1964 
below notch; lower margin of cutting edge equal 
to half the length of the entire cutting edge; 
second maxilla broadly rounded, spines lacking 
along median portion of inner margin; inner 
rami of cirri V and VI atrophied; penis with 
long setae and short, sharp spines scattered over 
surface, inconspicuously annulated, without mi- 
nute, specialized, rivet-like structures. 
DESCRIPTION: Capitulum (Figs. 3 A, B) ovoid 
in lateral aspect, carinal margin broadly convex; 
convex curvature of occludent margin inter- 
rupted by protuberant lips of orifice; carinal 
ridge, when present, indistinct (the animals 
were received dry and one cannot tell how much 
the effect of drying is responsible for the condi- 
tion of the indistinct carinal ridge); no other 
prominent distinguishing warts, bumps or pro- 
tuberances were observed other than an incon- 
spicuous but definite thickening, a little less than 
one-half the distance up the carinal margin of 
the capitulum. This thickening is rather peculiar. 
In two specimens (including the holotype) a 
small tear or perforation, communicating with 
the mantle cavity, was evident at the upper 
end, and in one specimen the cirri protruded 
through to the outside. U-shaped orifice rela- 
tively small, approximately one-fourth the height 
of the capitulum; slightly crenulate lips con- 
tinuous above but not below; mantle wall thin, 
cuticle smooth, except where marked by fine 
lines and minute folds about the orifice and at 
the capitulo-peduncular junction. Dried speci- 
mens were an opaque, reddish-brown color. 
Peduncle essentially one-half length of capitu- 
lum, about as long as wide, marked by several 
folds and by fine lines in the otherwise smooth 
cuticle; basal portion of peduncle expanded into 
attachment disc; holotype UCMP 37863 (Figs. 
3 A, B) measured: 
Capitulum Peduncle 
Length: 1.6 mm 0.85 mm 
Width: 1.4 mm 0.85 mm 
Depth: 1.6 mm — 
Labrum (Fig. 3 C) slightly bullate, anterior 
portion covered with numerous long, fine, soft 
setae; crest supporting 12-14 equally spaced, 
small, sharp teeth; sides of labrum, posterior to 
insertion of palps, finely squamous. Palp (Fig. 
3 C) nearly triangular, superior margin support- 
ing several long spines, outer surface sparsely 
scaled. Mandible (Fig. 3 D) with five teeth 
