Genera and Species of Starfishes. 17 



Family Poraniidae. 



Rhegaster, Sladcn, 1883, p. Ljo. Type, E. murrayi 

 (Sladen). 



Tliis gejieric name has jjriority over Lasiaster, Slad., 1889, 

 and Poraniomorpha (type P. rosea, Daniels. & Koren, 1884), 

 even if they are all tlie same genus, as stated by Grieg 

 (1906), and" by Sussbach and Bieckner (1910, p. 219). Yet 

 the authors last named adopt Lasiaster as the name of tiie 

 genus. The type of the latter was L. villosus, Slad., 1889. 

 These authors consider villosus^ rosea, and murrayi synonyms 

 of Goniastcr hispidiis, Surs, 1871, and adojtt the latter 

 spi'cific name. 



With ''^ L. kispidus^^ they also unite the two American 

 species — Rhec/asttr s/)innIosiis, Verrill, 1879, as Porania ; 

 and R. horealh^ Verrill, 1878, as Asteriaa. B 'th were later 

 (1895) referred by me to Poraniomorpha^ because reco<,aiized 

 as closely related to the type, P. rosea, Daniels. & Koren. 

 However, there is no evidence that the two American forms 

 belong to one species, whether either be identical with that 

 of Northern Europe or not. Indeed, they are very distinct 

 in the character and arrangement of their dorsal spinules 

 and plates, and still more so as to the interactinal spines and 

 plates. 



Rhegaster borealis, Verrill, 1878 (in part., 1895, p. 139). 

 (PI. I. fig. 1.) 



This has the entire dorsal surface and suj)eromarginal plates 

 densely covered with uniform, miimte, obtuse, erect, miliary 

 spinules, each terminated by a circle of microscopic points, 

 giving the surface a plush-like appearance to the naked eye, 

 and without any visible outlines of j)lates. In this respect 

 it agrees well with R. murrayi, Sladen, which also has the 

 same sort of thorny-tipped spinules, and similar papular 

 pores and adambulacral spines. 



Yet the under surface is quite different, for in R. borealis 

 the interactinal plates are clearly defined, and each one bears 

 a conspicuous group of acute, elongated, erect, and divergent 

 ppinelets, much longer than the dorsal ones, about six to ten 

 on a plate. The plates are large, convex, imbricated in four 

 rows parallel to tiie marginals. The inferomarginal plates 

 are large, terminated by a crowded group of twenty to thirty 

 spinelets, similar to the interactinal ones. As to the under 

 side it is, therefore, more like Lasiaster villosus, hnt yet quite 

 different in its spinulation, and cannot be considered the 

 same species. 



Ann. ct- Mag. X Hist. Ser. ><. Vo/. xiv. 2 



