103 
sides of the mouth-edges and through the arms being considerably 
longer. Further the papillæ, or armspines, afford a characteristic 
difference (Fig. 2). In O. sibogæ the outer spine is almost as long 
as the inner one, the latter being provided with some larger, 
straight thorns on the adradial side in its outer part; in O. long- 
ipes the outer spine is, at most, two thirds the length of the inner 
one, which latter is pro¬ 
vided in its outer part, 
on the adradial side, with 
a great number of strong, 
curved thorns. To this 
thorny part of the inner 
spine is attached a giand 
which is much larger in 
longipes than in sibogæ; 
the more or less distinet, 
claviform shape of this 
spine is mainly due to 
the different develop- 
ment of this giand, which 
appears to be of very 
common occurrence in 
Euryalids, and the se- 
cretary funetion of which 
has no doubt some important bearing on the biology of these forms. 
The greater length of the arms in O. longipes might seem to 
be no real difference from O. sibogæ^ since H. L. Clark in his re¬ 
port on the „Endeavour“ Echinoderms (p. 80) records among his 
specimens of the latter species from the Bass Strait and the Great 
Australian Bight (80—300 fms) one of the same size and arm- 
length as the New Zealand specimen here made the type of O. 
longipes. Most probably, however. Clark’s specimens are in reality 
not O. sibogæ, but O. longipes. Clark, himself, expresses some 
doubt as to the correetness of identifying the Australian speci¬ 
mens with O. sibogæ; I would therefore think it probable that they 
do really belong to the New Zealand species. At least, the state- 
ments resting on these specimens cannot afford the proof of the 
identity of the New Zealand species with O. sibogæ, and, for the 
Fi;'. 2 Ai'mspines (papillæ). (rom about the niiddle or 
the arm, of Ophiocreas sibogæ (a) and Ophiocreas long¬ 
ipes (b). 12/]. 
