21G On the Occurrence of Pedicellaster in the Far North. 



stripes, which are filled with yellow silky pubescence. Elytra 

 at the base a little broader than the thorax, and nearly three 

 and a half times as long-, regularly attenuated posteriorly ; 

 each elytron with three yellow silky stripes, the middle one 

 impressed at the base, not quite extending to the apex of the 

 elytron. 



Uoh. Madagascar, Fianarantsoa. 



XIX. — Note on the Occurrence o/' Pedicellaster (Sars) in the 

 Far North. By W. Percy Sladen, F.L.S., F.G.S. 



In the " Report on the Echinodermata collected during the 

 Arctic Expedition, 1875-76 " (Ann. & Mag. Nat'. Hist. ser. 4, 

 vol. xx. ]). 449), a starfish obtained in Discovery Bay (hit. 

 81° 41' N., 25 fathoms) and off Cape Frazer (lat. 79° 44' N., 

 80 fathoms) was described under the name of Asteracanthion 

 palceocrystallus [l. c. p. 455). 



Owing to the very marked characters presented by this 

 form, it was not without considerable hesitation that the species 

 was classed as an Asteracanthion, and then only on account 

 of extreme unwillingness to burden the nomenclature of Aste- 

 roids with an additional generic term. Subsequent study, 

 however, of Captain Feilden's specimens and also of Sars's 

 original description and figures of Pedicellaster tyjricus* 

 (which the writer had not previously seen) leaves no doubt 

 that the form above mentioned ought to be referred to Sars's 

 genus. 



Pedicellaster is characterized by the true biserial arrange- 

 ment of ambulacral sucker-feet, the more or less regularly 

 quadrate arrangement of the ossicles composing the abactinal 

 network, the isolated spinelets borne mainly at the decussa- 

 tions, the general character of the spinulation together with 

 the fact that every appendage of the body is invested with a 

 thick semitransparent cuticular membrane, and, above all, by 

 the presence of pedicellariai forcipiformes (" pedicellaires 

 croises" Perrier) without the usual accompaniment of p. 

 forficiforrnes — an occurrence unknown in any other genus. The 

 pedicellarise also are of extraordinary size, being but little 

 less than the dorsal spinelets, and stand isolated upon the 

 membrane that stretches over the intermediate spaces of the 

 calcareous network of the body-frame, their form at the same 

 time being undoubtedly characteristic. 



* Overset af Norges Eehinodermer, pp. 77-84, pi. ix. figs. 7-17, pi. x. 

 fiffs. 1-10. ^ 



