MOLLUSCOlDA. 
313 
u Ponits surface, and give it a very peculiar, but not very attractive, ap- 
pearance. The flavour of those molluscoids is very strong, which does 
H however, hinder the poorer dwellers on the sea shore from eating 
them. The genus Phallmia is another type of the group. PliaUusta 
9r<m ularia is of a reddish colour, and about the size of a currant- 
Wy : it usually lodges itself in the oysters of certain localities. At 
^stend another species, Phallmia ampulloides, is found in prodigious 
quantities in the oyster parks, and is parasitic on living lobsters. 
Social Ascidians comprehend living Tunicata, connected together 
011 a common prolongation by the roots, hut free and unconnected m 
al1 other respects. Ascidia pedunculata (Fig. 125) may be quoted as 
example. 
The Composite Ascidians are still more intimately associated together ; 
a great number of these little 
eing s i; ye together in a 
^ B gle mass. Such are the 
B °t*ylla and the Pyrosoma. 
The Botrylla is a genera 
most interesting of all 
, 6 groups under considera- 
; ! °U- Only imagine from 
e u to twenty individuals, 
( ' v a,l i n f omij more or less 
Iptened, adhering by their 
0j - 8a b surface to some sub- 
^ a rine body, and holding on 
■■ their sides, so as to form 
a s °i't of wheel. “ When we 
6Xft ite one of the branches,” 
j ays Fredol, “a single mol- 
Use contracts JTtself; when 
touch the centre, they all 
,p 6la to contract themselves 
-it UV * ei The buccal orifice is 
the outer extremity of the 
a( lius ; h u t the intestinal 
filiations abut! on the 
tQr mnon cavity, which occupies the centre of the wheel. me we 
Fig. 125. Ascidia pedunculata (Milne Edwards). 
