VAN NAME: COMPOUND ASCIDIANS. 
401 
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soL- 
ov- 
a large base. Surface generally evenly rounded, sometimes irregular 
in large specimens, smoothish, but thinly 
covered with minute, firndy adherent parti- 
cles of fine sand which are embedded in the 
common tissue and scattered throughout its 
substance. The cloacal openings are few 
in number and irregularly placed, except in 
small specimens, which usually have but 
one large central opening. The animals 
often form somewhat circular groups of six 
or eight individuals around the cloacal 
openings; outside of the circular groups 
they are usually irregularly scattered, but 
sometimes form linear series of eight or ten, 
and in young specimens with but one cen- 
tral opening they often form a larger outer 
circle, which is near the margin, more or 
less irregular and composed of numerous 
individuals .... Color of the masses pale yel- 
lowi.sh or grayish; stomach dull orange color; 
ovaries yellowish white. The larger speci- 
mens are 15 mm. to 25 mm. in diameter" 
(Verrill and Smith, 1873, p. 705). 
Alcoholic specimens vary much in the 
shade of color of the common test, which 
ranges from a milky yellowish white to rather 
dark brownish gray, but the small closely 
crowded and usually much contorted zooids 
are generally visible through the test, though 
any arrangement of them in systems cannot 
generally be recognized. The amount of 
sand in and on the surface of the test is very 
variable; in some specimens it is insignifi- 
cant. In form and size, the specimens 
mostly agree well with Verrill's description, 
and though there are irregularly shaped col- 
onies among them, as would be expected in 
large series, it is evident that anything approaching the capitate form 
characteristic of A. glabrum is only infrequently met with in this spe- 
^t 
Text - fig. 22. — Aplidium 
paUidxim (Verrill). Zooid. 
X 42. The longitudinal mus- 
cle bands in the mantle are in- 
dicated in the figure. 
