162 BULLETIN "6, UNITED STATES NATIONAL MUSEUM. 



Subfamily CS-ONIA-STKRINJE "Verrill. 



Genus *ROSASTER Perrier. 



Genus •NYMPHASTER Sladen. 



Genus "NEREIDASTER Verrill. 



Genus *MEDIASTER« Stimpson. 



Genus *CERAMASTER (Verrill) including PHTILONASTER Koehlep. 



Genus *PLINTHASTER (Verrill) including *PYRENASTER Verrill. 



Genus •LITONOTASTER Verrill. 



Genus EUGONIASTER6 Verrill. 



Genus "PELTASTERc Verrill. 



Genus *TOSIA'i Gray. 



Genus »PENTAGONASTER ' Gray. 



Genus *SPH/eRIODISCUS Fisher./ 



Genus *GONIASTER Agassiz. 



Genus *AMPHIASTER Verrill. 



Genus •GONIODISCASTERff Clark. 



Genus *ICONASTER Sladen. 



Genus ♦ASTROCERAMUS Fisher. 



Genus JOHANNASTER Koehler. 



Genus *CALLIDERMA Gray. 



Genus *CALLIASTER Gray. 



Genus MIUTELIPHASTER Aloock. 



Genus *GILBERTASTER Fisher. 



Genus CIRCEASTER Kcehler. 



Genus LYDIASTER Koehler. 



Genus *CLADASTERA Verrill. 



o Mediasler is placed by Perrier in the Astrogoniinse, that is, the Pseudarchaeterinje. There is much 

 to be said in favor of this classification. Verrill placesthe genus, along with Nymphasicrand Nereidaster, 

 in a special subfamily Mediasterinse. There is no subfamily difference between Mediaster and Ccra- 

 mastcr, and to include the latter in the Mediasterinse would be to anne.x species which some writers even 

 now csU Tosia and I'cntagonaster. Ceramaster forms a perfect connecting link between Mediaster and 

 its allies and Pentagonaater and its allies. All the genera near Mediaster (Rosaster, Nymphaster and 

 Aereidaster) arc near the typical Goniast.erinje in the structureof the actinal intermediate, adambulacral, 

 and mouth plates, and in having always true bivalved or foraminate pedicellariie. These are always 

 lacking in the Pseudarchastorinsp, where the pedicellariae, if present, are spiniform-fasciolar, or are incip- 

 ient bivalved, and derived from the former. I have merged the Mediasteringe with the Goniasterinae. 



6 Type, Pentagonaster investigatoris Wcock. " Eugoniaster is related to Peltaster but differs in having 

 the abactinal plates all small and similar, and also naked centrally, and in having the marginal plates 

 mostly naked, except around the margin. The large bivalved pedicellariae are similar in the two 

 genera." (Verrill.) The genus differs from Plinthastcr in the character of the pedicellaria^, and in the 

 adambulacral armature, which is graded from the furrow to the actinal surface. There are no secondary 

 plates, and the abactinal plates are flat and rounded. The actinal plates are granulated. 



c Peltaster Verrill, 1899, p. 168; type, P. hebes Verrill =Goniastcr nidarosiensis Storm, 1881 (Grieg, 

 Bergens Museums Aarbog, 1905, No. 3, p. 3). I have seen the type in the Yale Museum. 



^ Tosia Gray, 1840 (Dec), p. 281; type, T. australis Gray; monotypic. There are numerous speci- 

 mens of T. australis in the Museum of Comparative Zoology. 



<See notes on Pentagonaster, beyond. 



/For diagnosis, see notes beyond. 



ff Notes on some Australian and Indo-Pacific Echinoderms. Bull. Mus. Comp. Zool., vol. 52, No. 7, 

 1909, p. 110. Type, Asterias pleyadella Lamarck: see notes below. 



^CladasUr may be, with reason, placed in the liii)pasteriin8e. The genus lacks entirely, however, 

 theabactinal secondarj' plates which are characteristic of the three genera placed in the Hippasteriin*, aa 

 well as the characteristic aV)actinal and marginal tubercles and bivalved pedicellariae. The abactinal 

 skeleton therefore does not differ materially from that of Tosia or Pentagonaster. Cladaster could be 



