51 
the other species of the genus Ophiocoma in having hollow arm¬ 
spines as also in having a large and thick peristomial plate, this 
plate being narrow, linear, divided in two pieces in the other 
species. — Although stating that the character of the hollow spines 
draws this species towards the genus Ophioconis , Ly man leaves 
it in the genus Ophiocoma, to which it was referred by the pre- 
vious authors (Forbes, Muller & Troschel, Lutken), and 
there it has remained until now H. L. Clark in his Catalogue of 
Recent Ophiurids p. 205 has taken the rather startling step of re- 
moving it to the genus Ophiacantha , and moreover of changing 
the old species name nigra (O. F. M.) into sphærulata Pennant, 
designating it thus Ophiacantha sphærulata (Penn.). Before giving 
up the old, well known name of this common Scandinavian Ophiu- 
rid, however, a careful examination of the questions involved is 
needed. It is evident, that only the most cogent reasons can induce 
us to follow Clark in adopting that totally unfamiliar name instead 
of the name Ophiocoma nigra, familiar not only to all the natur¬ 
alists of Scandinavia and Northern Europe, but, it may well be 
said, to Zoologists in general. 
There are two main questions here: 1) to which genus it should 
really be referred, 2) the identification with Pennant’s „Asterias 
sphærulata". 
The differences between O. nigra and the other species of 
Ophiocoma pointed out by Ly man are real enough; especially 
the character of the spines is a noteworthy difference. To this I 
would add another conspicuous difference. In all the tropical spec¬ 
ies of Ophiocoma the teeth are provided with a very conspicuous 
point of an enamel-like structure (also found in Ophiomastix) ; in 
O. nigra the teeth are devoid of this structure. (Lyman, Chall. 
Oph. p. 168, mentions this point in the anatomy of Ophiocoma, 
stating that the teeth have „a quasi-enamelled grinding end“ and 
gives a figure therof, PI. XLII, Fig. 13, which does, however, hardly 
convey a very good impression of this striking feature; he does 
not notice that it is not found in O. nigra). — It seems to me 
that these points of difference are really of sufficient weight for 
removing our North Atlantic species from the genus Ophiocoma. 
— Most probably also the larvæ will prove to differ essentially; 
howewer, this point is not yet sufficiently established. 
4 * 
