46 
of my examination of quite an extensive material of the two named 
forms is absolutely at variance with the result arrived at by Grieg, 
whereas I must, upon the whole, confirm the statements of M. 
Sars (Norges Echinodermer, p. 8—12). I hope the following notes 
will convince also Grieg that there cannot be the slightest doubt 
that O. purpureus is a very well distinguished species, which — 
Fig. a, c, d. Ophioscolex purpureus ; b, e. O. glacialis. a, b. ventral side, d, e. dorsal 
side, showing radial shieids and base of arm. c. side view of arm, outer part. 6 /i. 
on a doser examination — is always easily distinguishable from 
O. glacialis. 
The mouth papillæ do not afford any very reliable distinction 
between the two species; but, upon the whole, they are somewhat 
more numerous in purpureus than in glacialis , as mentioned by 
Sars; they are generally 6 —10 in purpureus , distributed along 
the whole mouth edge, the two outer ones being as a rule larger 
than the rest; in glacialis there are 3 — 6 papillæ, situated at the 
inner part of the mouth angle, in larger specimens sometimes with 
an irregular bunch of papillæ at the point. The mouth shieids and 
adoral plates afford more reliable distinguishing characters, espec- 
ially the latter. In glacialis the mouth shieids are small, triangular, 
and the adoral plates carry a spine, sometimes two> 
