278 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



Comaster minima*. Amphimetra spectabilis, 



Comaster multil>rachiata. Stephanometra echinus. 



Comaster fruticostis. Stephanometra monacantltn. 



Comaster distincta. Oxymetra flnschii. 



Comaster parvus. Oxymetra aranea. 



Comaster taviana. Dichromctra ciliata. 



Comaster delicatn. Dichrometra flagellata. 



Comantheria polycnemis. Mariametra suocarinatn. 



Comantheria briareus. Lam.prometra palmata. 



Comanthina schlegelii. Lamprometra protectus. 



Comanthus pingni-s. Cenometra unicornis. 



Comanthus solaster. Cenometra delicata. 



Comanthus japonicus. Cenometra herdmani. 



Comanthus trichoptera. Cyllometra disciformis. 



Comanthus benhami. Cyllontetra albopnrpurea. 



Comanthus wahlbergii. Oligometra serripinna. 



Comanthus samoana. Antedon petasus. 



Comanthvs annulata. Antedon biflda. 



Comanthus parvicirra. Antedon adriatica. 



Zygometra microdiscua. Promachocrinus kcrgiieJennis. 



Zygometra elegans. Fariometra explicata. 



Catoptomctra magniflca. Trichometra vexator. 



Himerometra magnipinna. Thaumatometra nutrix. 



Himerometra robustipinna. Thaiimatocriniis rngosits. 



a 1 . Definite plates present In the ambulacra] lappets or In the lateral perisome of the pinnules 



between them and the pinnulars, or In both situations. 

 6 1 . Two series of plates or splcules present ; a plate or spicule in each ambulacra! lappet and 



another between this and the border of the pinnulars. 



c l . Plates of both series large, conspicuous and highly developed, the lateral perisome of 

 the pinnules and the ambulacral lappets being completely inclosed by them: 

 plates iu the lappets more or less circular, oval, or reniform ; lateral plates with n 

 narrowly produced distal and broad proximal process, and on the inner side two 

 prominent ridges, the distal curved and usually interrupted, the proximal straight, 

 at right angles to the pinnulars, and carrying the covering plate articulated to 

 the outer end. 

 d 1 . No supplementary side plates present. 



e 1 . The sacculi do not pierce or notch the side plates. 

 Ptilometra macronema. Pterometra magnipeda. 

 Ptilomftra milUeri. Pterometra splcndida. 



Asterometra anthug. Pterometra puiclicrrimn. 



Asterometra macropoda. Pterometra tricJiopoda. 

 Asterometra cristafa. 

 e'. The sacculi reach the exterior through boles in the side plates, or through 



gaps between them formed by two apposed notches. 



f. The outer portions of the saeculi pass to the exterior through apertures 

 formed by two rounded notches in the adjoining ends of adjacent 

 plates. 



Keometra alecto. Caloinetra fliscoidea. 



Neometra acanthaster. GcpJiyrometra propinqua, 



yeometra conaminis. Pectinometra cnrduum. 



ffeometra gorgonia. Pcctinometra flavopurpurca. 



Calometra callista. Ptilometra macronema. 



