272 Annals of the South African Museum. 



those of the inner sides are quite markedly compressed; on the sur- 

 face of each plate is a single, stout spine. 



P.F. 17997. Cape Point, N. E. 3 ,, N., 39 miles, 310-500 fms. 

 Gn. m. 1 specimen; young? 



A specimen of phrygiana taken by the CHALLENGER on La Have 

 Bank, south of Nova Scotia, in which R = about 57 mm. is much 

 like A in form and proportions but in its adambulacral armature it 

 is much like B. On the other hand, a specimen with R = 48 mm., 

 collected near Grand Manan, has so many big nearly spherical 

 tubercles on the abactinal, marginal and actinal plates that its 

 general appearance is quite different from any of the others; the 

 adambulacral armature approaches that of A but the big furrow 

 spine usually has a very small spine adoral to it and sometimes an 

 aboral one is present also. 



There is little question that Hippasteria phrygiana is very varia- 

 ble. Possibly more than one species is now included under that 

 name or it may be that varieties or subspecies should be recognized. 

 But until the growth changes are known and a large series of spe- 

 cimens from many localities has been gotten together and studied, it 

 seems to me best to let a single name cover all the Atlantic 

 forms of Hippasteria. 



OREASTERIDAE. 



There is only a single specimen in the South African collection 

 to represent this well-known tropical family of big sea-stars. Four 

 other species have been reported from South Africa however, so the 

 family is better represented there than the present collection indi- 

 cates. Nevertheless it must be granted that South Africa is a little 

 too far outside the tropics for even such a ubiquitous warm-water 

 genus as Oreaster to flourish, and probably south of Mozambique, 

 the Oreasteridae are represented chiefly by stragglers. It is an easy 

 matter to distinguish the few species that have been recorded 

 hitherto. 



Key to the South African Species of Oreasteridae. 



Rays well developed. 



One or two distal superomarginals on each side of each ray bear a very big 

 spine, while the remaining marginal plates are merely a little tumid and 

 carry no spines ...... Oreaster linckii. 



Superomarginals without spines or with small or moderate ones on many 

 plates, especially in interradii . . . Oreaster mammillatus. 



Rays very short or apparently wanting, as the body is thick and cushion like, 



and pentangular or roughly circular. 



