206 PEOF. p. M. dfncan's eevisioi? of the 



Genus Echinocorys. 

 Subgenus Jeronia. 

 Genus Holaster. 



Subgenus Lampadaster. 

 Genus Offaster. 



Hemipneustes. 

 Cardiaster. 

 Subgenus Infulaster. 

 Genus Hagenowia. 



Subfamily UrecTiinincd. Ambulacra uuiporous. 



Genus Urechinus. 

 Cystechinus. 

 Calymne. 



Incertse sedis : EnicJiaster. 

 Stenonia. 



Genus Echinocoets, Breynius, 1732, Sched. de 'Ech. p. 58, pi. iii. 

 fig. 2. lyOrb. 1853, Fal. Frang., Terr. Cret. vol. vi. p. 62. 

 Loven, 1874, Etudes, figs. 51-53, 97, 181. 



Syn. Ananchytes, Lmk. ; Oolaster, Laube, 1869. 



Test large, thin, oval in marginal outline, flat actinally, straight 

 or tumid at the sides above the sharp margin, high, rounded, or 

 keeled apically. 



Apical system elongate ; usually the four basals are all per- 

 forated by genital ducts ; but the foramen may be absent in the 

 plate with the madreporite, or the right anterior basal plate ; the 

 antero -lateral radial plates large and united and separating the 

 anterior and posterior pairs of basal plates. 



Ambulacra nearly similar, all flush, apetalous, biporous, the 

 plates low and narrow near the apex and gradually increasing in 

 width and height to the margin, and small and dissimilar at the 

 peristome ; pairs of pores well developed abactinally ; pores round 

 or oval and nearly horizontal, becoming smaller, closer, and ob- 

 lique towards the ambitus, where the pairs are more distant ; at 

 the peristome the adoral pore of a pair is in front of the abgral 

 pore and separated by a nodule. Posterior ambulacra actinally 

 long and broad, the pairs small and the pores oblique. 



Interradia with large plates ; the postero-lateral areas unsym- 

 metrical actinally, from union of the second plates of both zones 

 behind the peristomial plate of the right posterior area ; all the 



