Verrill, JSfotes on Radiata. 269 



A medium-sized specimen has arms '5 of an inch in length, with the 

 disk '16 in diameter; the two largest yet examined have the disk -22 

 in diameter. It is quite probable that all these specimens are young. 



Pearl Islands, Bay of Panama, — F. H. Bradley.* Among the inter- 

 stices of a branching sponge, associated with two species of Ophiac- 

 tis, about a dozen specimens of variovis sizes were found. Others oc- 

 curred in colonies clinging to the branches of Gorgoniaj and Muricete, 

 with the arms wound closely around the branches. 



Subgenus, Ophiothela nov.f 



The name Ophiothela is here employed to designate a group of 

 Ophiurians, of which the preceding species is the type, agreeing to- 

 gether in having the upper arm-plates covered with granulations as in 

 Astrophyton ; in having short, rough arm-spines, mostly turned down- 

 ward, and armed with roughnesses or hooks, beneath, as in Ophiactis ; 

 in having very large radial shields, covering most of the disk, the in- 

 tervening spaces being covered with a skin and bearing simple spines ; 

 in having the lower side of arms and disk covered with a skin, more 

 or less obscuring the plates ; and in having the mouth-shields and 

 side mouth-shields united into a ring around the mouth. The present 

 species and another from the Fejee Islands have, in the numerous 

 specimens observed, always six arms, and have the same habit of 

 clinging closely around the branches of Gorgonvv. 



In the structure of the mouth it agrees well with the typical spe- 

 cies of Ophiothrix, but it differs in having the arms distinctly cov- 

 ered with a membranous skin, and their upper surface granulated; 

 and in the character of the spines of the arms and disk, which lack 

 the glassy appearance and prominent thorny branches, and approach 

 more nearly those of Ophiactis in fonn, structure, and arrangement. 

 Although intermediate in some respects between Ophiothrix and 

 Ophiactis, it is evident that these species are more closely allied to the 

 former genus, under which I have placed them as a subgenus. 



Additional Remarks on Ophiiiridce. 



Owing to the small number and imperfect condition of our speci- 

 mens of some of the species of Amphiura and Ophiactis I have been 

 obliged to leave them somewhat in doubt and, in order to avoid pro- 

 ducing any confusion, have in such cases preferred quoting the orig- 

 inal descriptions instead of giving new ones. This seemed still more 



* More recently from Cape St. Lucas and La Paz, — Reprint. 



f This has since been regarded as a distinct genus (p 376). Besides this species and 

 0. BanoBY., Feejee Is., a species occurs on Mopsella from Japan (Dall), and Parisis from 

 Formosa (Lijtken), — Reprint. 



