ASTEROIDEA OF NOKTH PACIFIC AND ADJACENT WATERS — FISHER. 173 



(P. Appressed, distinct, sharp actinal intermediate Bpinulee, in addition to the close granulation. 

 «'. Distal superomarginal.i contiguous; appres-sed inferomarginal spine.'; conspicuous enlarged 

 actinal adambularral apine.s; marginal plates forming square edge to disk. 



Calliderma Gray, 

 e*. Distal superomarginab not contiguous; no inferomarginal spines; no enlarged adambu- 



lacral spines; marginal plates forming rounded edge to disk Johannasler Koehler. 



(?. Abactinal plates of rays polygonal, flat, conspicuously larger than those of disk; marginal 

 and actinal plates granular, armed with pedicellarise, but without spines; no enlarged 

 adambulacral spines; disk large, rays long; superomarginals at first increai<ing, then grad- 

 ually docrea-iing in size. 

 d". With bivalved pedicellariss (type of Jlippasteria, Cladastcr, Gilherlaster); abactinal plates 

 irregularly polygonal, bordered by a single series of granules, with or without a few scat- 

 tered granules on surface; plates or rays abruptly larger than those of disk. 



Circeaster Koehler. 

 eP. With spatulate excavate pedicellarice; abactinal plates of rays larger than those of disk 

 but transition not abrupt; abactinal plates flat, bordered by single row of granules, and 

 with a few granules and a pedicellaria on surface; otherwise as in Circeaster. 



Lydiaster Kahler. 



c?. Body covered by a membrane, which usually obscures the outlines of underlying plates and 



which may have a smooth surface (the granules when present being beneath the skin) or may 



be closely beset with small granules (as Stellaster). 



6'. Actinal intermediate areas small; abactinal plates hexagonal or rounded, each with a short 



obtuse spinelet or tubercle; adambulacral armature a transverse series of three large obtuse 



spinelets; pedicellarise if present bivalved Chilonasler Sladen. 



6^. Actinal intermediate areas large; abactinal plates polygonal, .sometimes somewhat .stellate; no 

 spines on abactinal surface, rarely a few short tubercles; adambulacral armature a furrow 

 comb, and on the actinal surface either granules or an enlarged flattened spine; slit-like 

 bivalved pedicellaria or two-jawed pincer-shaped pedicellariae. 

 f'. Membrane superficially smooth; granules, if present, beneath the membrane. 



d'. Abactinal membrane very thin, without granules; no secondary abactinal plates in the 

 radial areas; no marginal granules or spinelets, nor actinal intermediate granules 



Ogmaalcr v. Martens. 

 eP. Abactinal membrane fairly thick and obscuring (unless dried) the outlines of underlying 

 plates; secondary small abactinal intermediate plates on either side of the median 

 radial series, sometimes more extensively distributed over radial regions." 

 e'. Superomarginals without conspicuous granules, spinelets, or pedicellariae. .Vctinal inter- 

 radial areas with slit-like bivalved pedicellariae in addition to hemispherical granules. 



Anthcnoidcs Perrier. 

 e-. Superomarginals with granules or a few short spinelets or only a few small papilliform 

 pedicellarise; no slit-like bivalved pedicellarise, but actinal intermediate area with 

 or without papilliform pincer-shaped pedicellarise. 



Leptogonaster Sladen (incl. Antheniaster Verrill). 



c*. Membrane closely beset with very small crowded granules. Abactinal plates polj-gonal or 



Bubstellate; inferomarginal plates with a flattened mobile spine; bivalved pedicellarise 



flush with surface, frequently several papulae to an area Stellaster Gray. 



III. Abactinal plates circular to substellate, separated by numerous secondary plates which are either 

 independent or else join the primary plates forming a close reticulated skeleton; in the latter 

 case, when viewed internally, the secondary plates appear as short rather irregular o.-<sicle3 

 passing between the large primary plates, so as to form a sort of heavy reticulum; but super- 

 ficially they appear as ordinarj' plates of smaller size; abactinal skeleton not overlaid by a thick 

 skin; a rather thin pulpy membrane sometimes present, partially obscuring the plates; pedi- 

 cellarise typically large, bivalved or with spatulate wide or narrow jaws. Adambulacral spines 

 of both series heavy, comparatively few, those of actinal surface of plate always few and heavy; 

 usually robust marginal spines present IUppattrriinx. 



o Often lacking in very young specimens. 



