534 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
appearance and feeling, like fine sandpaper, due to very minute short 
stiff spines abundantly distributed over the surface, singly or in small 
groups of from two to six or even more, each single spine, or each 
group, being raised on a small rounded elevation. On some specimens 
single spines, on other groups predominate. About the orifices the 
spines are longer but rarely sufficiently so as to be very conspicuous. 
The spines do not branch but (especially in the case of the larger ones) 
there may be slightly projecting points along the sides or at the base. 
" Color generally yellowish white, more or less tinged on the upper 
part and one side with peach-red; frequently yellowish white through- 
out, or merely tinged with orange in certain parts, especially between 
the tubes. Not unfrequently the color is deep orange-red or peach-red 
over most of the surface, except the lower part of the sides, which are 
flesh-color or salmon-color, and a band of light orange bordered with 
darker orange-red, which passes from each tube down the sides to the 
base; a similar band or spot generally exists between the bases of 
the tubes. The apertures are salmon-color inside, often surrounded 
by a delicate circle of red, or in the darker specimens with a pale orange 
circle" (Verrill, 1871a, p. 97-98). This vivid coloring together 
with its velvety appearing surface, has caused the animal to receive 
the popular name "sea peach." It attains a large size. The largest 
specimen measured was 75 mm. high and 54 mm. wide. The follow- 
ing description of the internal anatomy was prepared from specimens 
of moderate size, 30 to 40 mm. in height from the base to the end of 
the branchial siphon. 
Mantle usually readily separable from the test in preserved speci- 
mens. Musculature well developed over practically the whole body, 
consisting of an inner la^er of stout closely placed bands originating 
from the siphons and running to the opposite (attached) end of the 
body. Overlying these bands is a superficial layer or sheet of slenderer, 
less well defined bands, which cross the first mentioned bands at right 
angles, surrounding the body like the hoops of a barrel. This layer 
extends up on the siphons and forms their sphincters. 
Oral tentacles comparatively few. Not more than three or four 
orders somewhat regularly arranged according to the usual scheme 
(1, 4, 3, 4, 2, 4, etc.). Those of the first two orders apparently nor- 
mally number altogether eight, those of the third order eight, while 
the fourth -order tentacles are few and scattered. Even the largest 
tentacles are only simply pinnate with short stump-like but tapering 
