VAN NAME: COMPOUND ASCIDIANS. 343 
forms above listed, and that as already stated (p. 340) Stimpson (1854, 
p. 19) records finding at Grand Manan in one instance "what appeared 
to be a ClavcUina but so mangled by rough usage in the dredge as to be 
further indistinguishable." The occurrence of a member of this or an 
allied genus in these waters is not in itself improbable, but as a large 
amount of collecting has since been done in the above locality without 
finding any such form, Stimpson's record does not seem sufficiently 
certain to require further consideration in this paper. 
The writer has himself collected and studied in a fresh condition a 
number of the forms here described, but this account is based chiefly 
on the extensive collections of New England invertebrates belonging 
to or deposited in the Peabody Museum of Yale University, comprising 
those made by Professor A. E. Verrill, S. I. Smith, H. E. Webster, 
O. Harger, and others, chiefly during the years 1868 to 1870, inclusive, 
and those made (also largely under the direction of Professor Verrill) 
by the United States Commission of Fish and Fisheries between the 
years 1871, when it was first established, and 1887, inclvisive. Much 
of the material collected by the Fish Commission has been removed to 
the U»nited States National Museum at Washington, but the writer 
had previously examined most of the specimens of compound ascidians, 
and he feels reasonably sure that the account presented in the following- 
pages covers all the species that were collected. 
Not only did the combined collections, comprising in all hundreds 
of examples of compound ascidians from the region in question, afford 
an exceptional opportunity for the study of these animals on account of 
their richness in specimens and the extent of geographical area they 
covered, but they included the types of Verrill' s species and genera, 
and a large number of specimens from deep water, collected by the Fish 
Commission steamer Albatross, which could not be duplicated else- 
where. An examination of this material, which evidently contained 
forms new to the region, before time should play greater havoc with it 
than it had already done, was therefore very desirable. Naturally a 
part of these specimens were found in such poor condition that they 
were of interest chiefly in working out the distribution of the several 
species. Nearly all of them had simply been put in strong alcohol 
and kept in it, some of them for forty years, and were probably in many 
cases badly shrunken to begin with. Yet in the large quantity of 
material that was examined there were many remarkably well preserved 
colonies, in which the zooids were well expanded, and in which the 
