3S4 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
that species, have nothing to do with the present species, but with 
Didcmmim lufariam (see p, 374). 
Genus Didemnopsis Hartmeyer, 1903. 
[= DiDEMXoiDEs Lahille, 1890; not von Drasche, 1SS3; not Herdman, 1<S91.] 
Colony incrusting, often thick and fleshy. Spicules wanting. 
Branchial orifice six-lobed; atrial orifice situated on a funnel-like 
extension of the atria! cavity which is some distance back from the 
anterior end of the thorax. Three rows of stigmata. Testis single, 
of conical form. Proximal part of sperm duct coiled about the testis. 
Those members of the genus Trididemnum [Didemnum] which lack 
spicules in the test were separated for that reason by Lahille (1890) 
as the genus Didemnoides. As the name Didemnoides had already 
been otherwise employed (by von Drasche, 1883), Hartmeyer (1903) 
substituted the name Didemnopsis for the new genus. It appears, 
however, that both these names are antedated by Lioclinum, proposed 
by Verrill (1871a, p. 444) in a footnote to one of his papers. This 
footnote reads as follows: 
"Didemiutni, as established by Savigny and adopted by Milne 
Edwards, includes two distinct groups: the first having calcareous 
corpuscles in its integument; the second soft and gelatinous throughout. 
The latter may be called Lioclinum. It includes L. viscosum (Sav.) 
and L. (jekdinosum (Edw.)." 
The writer does not feel sure that it is justifiable summarily to reject 
Lioclinum in favor of Didemnopsis, as Hartmeyer (1909) has done. 
Didemnum viscosum Sav., a form which has not since been identified, 
is the type of Lioclinum as the species first placed in it. Should it be 
found again, and prove to be, as is very probable, a Didemnopsis, there 
would seem to be no question as to the validity of the name Lioclinum, 
for in this group we nuist depend on the characters of the type species 
more than on the generally imperfect diagnosis of the author in decid- 
ing the generic characters. But since the nature of Savigny's species 
remains uncertain, there is as yet no need of abandoning the accepted 
name Didemnopsis. Whether it is really worth while to keep this 
genus separate from Trididenmum [Didemnum] may after all be 
open to question. 
