180 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



frequently with an odd median s])ine at inner angle of combined plates. Pedicellarise 

 sometimes present, when they are either pectinate (formed of two opposing combs of 

 si)inelets over a transverse suture between actinal intermediate or adambulacral 

 plates) or are bivalved and evidently developed from the foregoing sort. Incipient 

 petlicellarise or postadambulacral fascioles are present on actinal interradial areas 

 and readily develop into pectinate pedicellariae. Small pincer-like pedicellariae 

 present rarely. Superambulacral plates present, often but feebly developed. 

 Tube feet with a well developed sucking disk. 



KEY TO THE SPECIES 01' r.SEUDARCHASTER HEREIN DESCRIBED. 



a". No trace of bivalvod pedicellarioe on first row of actinal intermediate plates or of pectinate pedicel- 



larim with conspicuously widened spinelcts; superambulacral plates not well developed; actinal 



intermediate and marginal plates covered with short swollen spinelets or granules. 



6 '. Paxillifi crowded; granulation of marginal plates close, the inferomarginals with low hexagonal or 



equamiform granules; abactinal paxillar area narrow on rays; actinal spinulation coarser and 



more granuliform; rays longer, disk smaller; postadambulacral fascioles parelii, p. 180. 



6^. Paxilla; usually well spaced with prominent papulae between; suj)eromarginals not prominent, 

 with spaced granules, a few conspicuously enlarged at outer end of plate; inferomarginals with 

 prominent enlarged spinules and spaced papilliform spinelets; rays broad and usually short; 

 actinal spinulation more delicate and spaced; pectinate pedicellariie sometimes present — simply 



more fully developed postadambulacral fascioles pusillus, p. 187. 



a^. Bivalved or bivalve-pectinate pedicellarise; actinal spinelets rather long and delicate on inter- 

 mediate plates; superambulacral plates well developed dusonus, p. 192. 



PSEUDARCHASTER PARELU (DUben and Koren). 



PI, 31, tigs. 1, 2; pi. 3:^, fig. 3; pi. 57, fig. 5. 



Astropecten parelii DtJBEN and Koren, Kongl. Svensk. Vet. Akad. Handl., 1844, 1846, p. 247, 



pi. 7, figs. 14-17.— M. Sars, Nyt Mag. for Naturv., vol. 6, Heft 2, 1850, p. 101. 

 Archaster parelii M. Sars, Ofversigt af Norges Echinodermer, 1861, p. 35, pi. 3, figs. 1, 2. — Verrill, 



Amer. Journ. Sci., vol. 7, 1874, p. 500; vol. 23, 1882, p. 140; Rep. U. S. Comm. Fish and 



Fisheries, vol. 11, 1884, p. 543. 

 Archaster parelii, xnT. longobradiialis Danielssen and Koren, Nyt Mag. tor Naturv., vol. 23, 



1876, p. 17; The Norwegian North Atlantic Exp., Asteroidea, 1884, p. 88. 

 Plulonaster (Tethyaster) parelii Sladen, Challenger Asteroidea, 1S89, pp. 83, 102, 122, 722,— 



Sluiter, Bijdr. tot do Dierk., Afl. 17, 1895, p. 51. — Sladen, Trans. Roy. Irish Acad., vol. 31, 



pt. 3, 1897, p. 78. 

 Plulonaster parelii Bell, Catalogue of the British Echinoderms in the British Museum, 1892, 



p. 63.— Norman, Ann. and Mag. Nat. Hist. (6), vol. 12, 1893, p. 346. — Grieg, Bergens Museums 



Aarbog, 1894-95, No. 12, 1896, pp. 5, 12; Stavanger Museums Aarsberentning for 1890, 1897, 



p. 37. — LuDwiG, Fauna Arctica (Seesterne), vol. 1, 1900, p. 449 (full synonymy of "parelii 



restricted," to 1897). 

 Pseudarchaster intermedins Sladen, Challenger Asteroidea, 1889, p. 115, pi. 19, figs. 3, 4; pi. 42, 



figs. 5, 0.— Verrill, Proc. U. S. Nat. Mus., vol. 17, 1894, p. 249; Amer. Joum. Sci., vol. 49, 



1895, p. 195; Trans. Conn. Acad., vol. 10, 1899, p. 190, pi. 25, figs. 1, la-b. 

 Pseudarchaster tessellatus, var. arcticus Sluiter, Bijdr. totde Dierk., Afl. 17, 1895, p. 51 (according 



to Ludwig). 

 Aslrogonium parelii Kcehler, Bull, de I'lnstitut oc6anographique. No. 99, April, 1907, p. 31. 



Diagnosis.— Rays five. R = 104 mm.; " r=37 mm.; R = 2.8 r. Breadth of ray 

 at basi". !J nun. Rays well developed, abruptly and arcuately tapering at base, 



"An unusually large specimen for this species, station 3225. 



