22 CONCHOLOGIST’S COMPANION. 
considerable numbers have been discovered within a 
few inches of each other. 
The pillars which supported the proud temple of 
Serapis at Puetoli, are so completely perforated by 
these industrious mollusc, as to present the appear- 
ance of honey-combs. Strange comment on the 
vanity of man! The sculptured columns of a temple, 
that was once so great and flourishing, where busy 
feet were heard, and active multitudes resorted, is 
now desolate and overthrown, and affords a shelter 
to innumerable shell-fish ! 
The animal inhabitant, which Linnzus calls an 
ascidia, resembles a fleshy membranaceous bag, 
nearly the length of the shell, and open at each end. 
It is furnished at the upper part with a cylindrical 
muscular tube, divided by a partition; at the lower, 
with a short, obtusely conical foot. The shell, in 
most species, is ovate, or oblong, formed of two large 
opposite valves, with several less, and differently 
shaped accessary ones, that act as substitutes for 
a hinge, which in bivalves. generally determines the 
generic character. 
The interior is colourless, or rather of a pure or 
dusky white, though it sometimes partakes of a 
brownish cast; this deficiency is, however, amply 
compensated by the beautiful fret-work with which 
