289 
the Magellanic region, makes it the more remarkable that Ben¬ 
ham did refer the New Zealand form to O. Grayi. The examination 
of the specimen presented to me by Captain Bol Ions and the direct 
comparison of it with a specimen of O. Grayi from the Magellanic 
region leaves no doubt but that the New Zealand form is a distinet 
species, which I take the pleasure of dedicating to Professor Ben¬ 
ham. Unfortunately the specimen is not in the very best condition, 
but, together with the information given by Ben ham, it is suffi¬ 
cient for ascertaining the distinetness of the species and for stating 
the characters in which it differs from the allied species. 
Is his splendid work on the Asteroidea of the Australasian 
Antarctic Expedition Koehler has given a very careful revision 
of the family of the Odontasteridæ (or Gnathasteridæ, which he 
maintains to be the more correct name). According to this the 
present species must be referred to the genus Peridontaster Koeh¬ 
ler, which differs from Odontaster s. str. in having larger, but less 
numerous marginal plates and in the spinelets of the paxillæ being 
mueh shorter. 
The specimen in hånd is a young one, only half the size of 
the two specimens examined by Benham. R=:17 mm, r— 8.5 mm; 
R =2 r. The arms are thus distinetly more prominent than in 
Benham’s specimens, which had R=l.87 r (by R=30 mm) and 
R=: 1.57 r (by R=33 mm); the facts thus known would seem to 
indicate that the shape becomes more pentagonal with age. 
The plates of the aboral side of the disk rounded, smaller on 
the arms than on the centre of disk and in the interradial areas; 
the papulæ are confined to the arms and to the centre of the 
disk. The midradial series of plates is distinet, the lateral plates 
less distinetly arranged in longitudinal series, parallel to the mid¬ 
radial series. The latter series continues to the point of the arms, 
while, according to Ben ham, in one of his specimens the three- 
four last superomarginals meet in the dorsal midline; in the other 
(largest) specimen only the last pair of marginals meet and only 
in two of the arms. The spinelets of the dorsal plates are short, 
somewhat coarser on the arms than on the disk; especially on the 
9 R. Koehler. Echinodermata Asteroidea. Australasian Antarctic Expe- 
dition 1911—14. Scientific Reports. Ser. C. Zoology and Botany. Vol. 
Vlll.i. 1920. 
Vidensk. Medd. fra Dansk naturh. Foren. Bd. 79. 19 
