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No. 11.— COMPOUND ASCIDIANS OF THE COASTS OF 
NEW ENGLAND AND NEIGHBORING BRITISH 
PROVINCES. 
BY WILLARD G. VAX NAME, PH.D. 
Introduction. 
The compound uscidian.s, or those that reproduce by budding and 
form colonies of more or less intimately connected individuals, are no 
longer regarded as constituting a natural group, since their origin from 
at least two, and perhaps more 'different groups of simple ascidians is 
well established. Yet those ascidians which have acquired this addi- 
tional method of reproduction, have as a result acquired so many 
characters in common that the division of the ascidians into simple 
and compound forms remains a most convenient one, the employment 
of which is still justifiable if made with the understanding that no 
natural classification is implied. 
In number of genera and species, the compound ascidians are fairly 
well represented in the New England region, and the abundance of 
certain of the species, as well as the large size of the colonies they form, 
would prevent their being overlooked by anyone making a study of 
its marine fauna. The scanty references to these animals in the 
earlier accounts of the invertebrates of this region are therefore to be 
explained chiefly by the difficulty of determining and satisfactorily 
describing the different forms of this group. In fact, until 1871, 
although the occurrence of other genera had been mentioned, but three 
of the species, those called in this paper Botri/Uus schlosscri (Pallas), 
Amaroucium peUucidum (Leidy), and Tetrad idemnum alhidum (Ver- 
rili), had been definitely determined and recorded. The earlier 
records are contained in the accounts of the Mollusca of this region, 
as the ascidians were then regarded as members of that branch of the 
animal kingdom. 
Couthouy, in 1S3S (see list of literature at the end of this article), 
records Botryllws schlosseri under the name B. sieUatus, and lists also 
" Polyclimim ?" from near Boston. The latter form cannot be 
definitely determined, but was probably Amaroucium glahrum Verrill, 
as no Polvclinuin is known from this reg-ion. 
