166 A. JE. Verrill — Revision Genera and Siyecies of Starfishes. 



This species is so similar to the last, in most of its characters, that 

 it might prove to be only a variety, if we had a large series for 

 study. But although the type is not much more than half as large 

 as that of T. compta, it has rather more marginal plates and more 

 numerous adambulacral spinules and actinal granules. The reverse 

 would usually occur in the young of this genus. Hence I am dis- 

 posed to consider it a very closely related, but distinct, species. 



Pyrenaster Ver., gen. nov. Type, P. dentatus Perrier. 



Form flat, more or less pentagonal, or stellate with a broad disk. 

 Rays tapered. Marginal plates rather large, those of the two series 

 similar and generally paired ; sometimes there is on one or more of 

 the margins {rarely on all) an odd interradial plate, — but this seems 

 to be more or less abnormal. 



In the type the upper marginal plates are partially naked, and the 

 abactinal plates usually have a small naked central area, surrounded 

 by marginal granules, but this is not constant. The upper marginal 

 plates in the type species are sometimes all separated by a row of 

 abactinal plates ; in other specimens of the same species two to five 

 pairs are in contact medially. Actinal and inferior marginal plates 

 granulated. 



Pedicellariae occur sparingly on the adambulacral plates ; they are 

 similar to the granules in size and height and have short chisel-shaped 

 blades. 



The dentary plates are large, ti'iangular, with numerous prominent 

 granules on the actinal surface, and with somewhat enlarged pris- 

 matic spinules on the oral margin. 



Adambulacral plates large, squarish, with 4 to V furrow spinules 

 in a regular marginal series ; these are decidedly more elongated 

 than the granules of the actinal surface and are separated from them 

 by a naked space, as in Mediaster. Distally these plates become small, 

 with the furrow end prominent and bearing a convex group of spin- 

 ules, while one or two of the spinules of the second row, on the 

 actinal side, become much longer and larger than the rest, as in 

 Tosia and most of the allied genera. 



The actinal plates ai-e flat, rather large, polygonal, crowded and 

 arranged in series parallel with the furrows. 



The abactinal plates of the radial areas are rounded, convex and 

 of two kinds, smaller, secondary, rounded plates being interpolated 

 between and around the larger or primarj'- plates. The smaller 

 plates are, however, of the same form as the others, and are granu- 



