ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER. 219 



Madreporic body circular, convex, situated one-third minor radius from renter 

 of disk; striations interrupted and moaiiilerin<j. 



Yottng. — The specimen from station 4407 has It about '-'.s nun. and r IS nun. 

 It may be an extreme variant of C. Icptocerama, but di(Tei-s marlcedly from that form 

 in the spaceil marginal granules and the enlarged actinal spinelets of the adam- 

 bulacral plates. The granulation of tiie actinal intermediate plates is Hke that 

 of cZa/ii, but the plates are more regular in form. The abactinal paxiUiform plate.s 

 are essentially like the type, but have fewer granules. 



r!/;;<'.— Cat. No. 27883, U.S.N.M. 



Type-loca1it>i. — Albatross station 477J, Bowers Bank, Bering Sea (lat. .14" 30' 30" 

 N.; long. 179° 14' E.) 344 fathoms, greenish-brown sand, one specimen. 



Distribution. — Southern Bering Sea to southern California, and from 334 to 

 600 fathoms. 



Specimens examined. — The type, and an immature specimen from station 4407, 

 between San Clemente and Santa Catalina i.slamls, Cahfomia, 334 to 600 fathoms, 

 rocks, shells, fine gra}' sand. The latter was in company with ('. leptoceramus. 



Remarls. — This species is characterized by the small marginals, with coarse 

 spaced granulation, by the coarse spaced actinal granulation, by the armature of 

 the adambulacral plates, and by the rather small abactinal paxiUiform ornate 

 tabula. The species differs from C. leptoceramus in lacking secondary abactinal 

 plates, in ha^^ng coarser actinal and marginal granules, much coarser and fewer 

 abactinal granules to each plate, fewer and longer furrow spinelets, and in having 

 the first series of the actinal adambulacral spinelets well developed and tubercular. 

 From C. japonicus, clarhi differs in all these points; especially striking are the 

 differences in abactinal and actinal granulation and in the forni and armature of 

 the adambulacral plates. 



Unfortunately there is only one undoubted specimen of this somewhat aber- 

 rant species. It is aberrant in that it departs distinct h^ from the t^-pe facies of 

 the genus (as exliibited by C. granulans and C. patagonicus) and shows a 

 tendency toward Mediaster. C. japonicus and C. leptoceramus are similarly aberrant 

 in a slightly different direction, possibly also toward Mediaster. Mediaster, Nymph- 

 aster, and Nereidastcr are closely relatetl and the gap between them and such genera 

 as 6onia.^ter, Pentagonaster, Tosia, Pelta-ster, Eugoniaster, and Plinthaster is bridged 

 by the various species of Ceramaster. So it does not appear possible to separate the 

 groups into two subfamihes, although the 'extremes, such genera as Media.iter or 

 Nym pilaster on the one hand and Goniaster or Pentagonaxtrr on the other, are 

 strikingly different. 



Named for Dr. Hubert Lyman Clark. 



CERAMASTER ARCTICUS (Verrlll). 



PI. 40, figs. 1, 2; pi. 58, fig. 1; pi. 60, fig. 1. 



Tosia arctica Verrii.l, .-Vmor. Journ. Sci., vol. 28, July, 1909, p. 63, figa. 8, 8<2. 



Diagnosis. — Arcuate pentagonal; R = 55 mm.; r = 34 mm.; R = 1.6 r (also 

 1.5 r). The short rays, or corners of disk, bluntly nnmded. Marginal plates 

 formuig an evenly rounded margin to disk, nnissive, with usually a slightly tumid 

 bare spot, and with largo flat crowded polygonal granules; bare spot sometimes 

 lacking on all but distal plates; either the i)eniiltimate or the last two superomar- 



