ASTEEOIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER. 241 



Ludwig (1897) has made Ohsetaster the type of a special family. 



KEY TO THE KNOWN OENERA OP MNCKIID.E. 



a'. Plates Bimply granulose, or covered with a thick pjanular or emooth ekin, hut not spiny. 

 6'. Abaclinal plates not forming regular longitudinal scrie.-i. 

 c'. Adambulacral armature spiniform, often subprismatic, in from one to three scries and scmctimea 

 resembling that of Goniasteriniv; disk usually well developed, \v-ith ray.-' tapering (\ardoa 

 frequently with small disk and narrow rays). 

 (f. Papultc on actinal surface as well as on abactinal. 

 e'. Adambulacral armature in twoor more series; papula? isolated; no superambulacral ossicles; 



rays flattened Fromia Gray. 



«-. Papulffi in areas; superambulacral ossicles; rays rounded; adambulacral armature in three 



series Nardoa Gray. 



cP. No papuhe on actinal surface, 

 e'. Adambulacral armature in one series; marginal plates not larger than others; no super- 

 ambulacral plates Ferdina Gray. 



e^. Adambulacral armature in two or three series (very like the Goniasterina>); marginal 

 plates conspicuous; rays rather triangular in section; superambulacral plates present. 



Jfarcissia Gray. 

 c'. Adambulacral armature granuliform in two or three series; rays slender, about same width 

 throughout; disk always small; superambulacral plates, 

 (f. No papuliB on actinal surface; papula; in areas, 

 e'. Rays more or less cylindrical; papula; in areas irregularly distributed among the abactinal 



plates Linclia Nardo, p. 242. 



e'. Rays trigonal; papula; in one or two continuous uninterrupted rows on either side of ray. 



PhaUtria Gray. 

 dr. Papulae single, on both abactinal and actinal surfaces; adambulacral granules in two series, 

 the outer much larger than the inner as in Ophidiastcr; marginal plates separated near angle 

 of disk by intermediate intermarginals; all plates bossed, separated by granules. 



BunasUr DOderlein. 

 6*. Abactinal plates in regular longitudinal series; adambulacral armature in two, rarely three, 

 unequal series, the outermost largest, sometimes siiiniform. 

 c'. Papuhe on actinal surface; superambulacral plates. 



d". Plates all granulo.se; that is, underlying a membrane of variable thickness covered with fine, 

 or coarse, often squamiform granules or papilla;. 

 «'. Papular areas not confluent laterally; madreporic body simple. 

 /*. Between the inferomarginal and adambulacral plates three series of actinal intermediate 

 plates and two series of papular areas; papular areas of the inner series twice as numer- 

 ous as in the other series Hacelia Gray. 



p. Only one ventrolateral (actinal intermediate) series of papular areas which are not more 



numerous than in the other longitudinal series Op/ridiattrr Agassiz. 



c'. Papular areas confluent laterally; madreporic body large and compound Pharia Gray. 



(p. Whole test covered with a thick smooth membranous investment Leiasia- Peters. 



c'. Xo papula; on actinal surface; superambulacral plates sometimes verj' small and covered by 



thick integument Opttiditulrr Agassiz. 



a'. Abactinal and marginal plates covered with membrane, the former, and occasionally the latter, 



bearing isolated skin-covered spinelets MetTodxTa" Gray. 



The above key differs from that of Sladori in the addition of two genera since 

 instituted and in tlie subordination of the suporambidacral phites. These are diffi- 

 cult to find in small specimens, and to base primary divisions on them is likely to 

 cause confusion. Perrier's key (1S04) is diliicult to work, having the same faidt as 

 Sladen's, in addition to ambiguity of expression in Section II A. 



o Scaphastcr de Loriol is a synonym. See Koehler, Ast^ries et ophiurea des ties Am ol Kei, Abh. 

 Senckenb. Naturi. Ges., vol. 33, 1910, p. 284. 

 57444°— Bull. 7C— It 10 



