VAN NAME: COMPOUND ASCIDIANS. 341 
greatly neglected by zoologists, the little that has been published 
being based almost entirely on Verrill's work, though Herdman (1886) 
described an Aplidiuin (A. dcspectum) dredged by the Challenger off 
Nova Scotia, which, without much doubt, is identical with one of 
Verrill's species, and Whiteaves (1901), in his "Catalogue of the marine 
Invertebrata of eastern Canada," gives new facts regarding the dis- 
tribution of some species. Lefevre's work (1898) on the budding of 
Perophora, Metcalf's (1900) anatomical observations, and Bancroft's 
(1903) investigations of the variations in the genus Botryllus should 
receive special mention as contributions to the anatomy and life history 
of certain forms. 
In general, however, the knowledge of this group as far as New 
England is concerned, stands today very much as Verrill left it more 
than thirty years ago, and his names for the species have up to this 
time been employed without any material changes. When these names 
were given, owing to the lack of good descriptions and figures of 
European forms, it was not possible to identify the New England 
species with those of the Old World, but the excellent descriptions and 
figures furnished by the works of Huitfeldt-Kaas, Hartmeyer, Bjerkan, 
Redikorzew, and other recent writers on the northern European asci- 
dians, clearly show that a number of the forms are common to both 
hemispheres, while the strict application of the law of priority in the 
nomenclature, which has been made possible through the admirably 
thorough and conscientious work of Hartmeyer, involves additional 
changes in these names. The species described by Verrill, with the 
names used by previous New England writers, and those changes in 
the nomenclature which the writer has adopted are as follow^s:, 
Verrill's name. Name here adopted. 
Botnjllus gnuldii. Botryllus schlosseri (Pallas), 1766. 
(= B. stellatus of Couthouy 
and Gould.) 
Botryllus sp.. Botrylloides aureum Sars, 18'51. 
Perophora viridis. No change. 
Leptoclinum nlhidum (type). Tetradidemnum albidum (Verrill), 
(= Didcmnium roseum 1871. 
Sars, of Packard, Bin- 
ney, and Dall.) 
Leptoclinum luteolutn (type). Tetradidemnum albidum (Verrill), 
1871. (Only a color variety.) 
