60 ECHINODERMA OF THE TNDTAN MtTSETTM, PART Vn. 



IS. Key to the Genera of OHARiTOMETRiDiE. 



a' IBr and further division series (when present) with a prominent tubercular 

 ornamentation , and a more or less marked tuberculous median keel ; rarely 

 more than ten arms. 



GLYPTOMETRA, p. 224. 



a- IBr and further division series (when present) without any tubercular orna- 

 mentation, and without a median keel. 



b' IBr segments and first two brachials with tlie proximal and lateral edges 

 produced, forming thin flange-like dorsolateral borders; ten arms. 



PCECrLOMETRA , p. 225. 



b* IBr segments and lower l)rachials witli the dorsolateral borders not pro- 

 duced, 

 c' third and fourth segments of the genital pinnules broad and nearly flat on 

 the outer side, but the fifth segment smaller; ten arms, 

 d' less than 12 cirrus segments; elements of the IBr series and arm bases 

 diverging at a wide angle so that the lower part of the animal is broad 

 and rounded. 



STROTOMETRA, p. 226. 



d^ more than 15 cirrus segments; IBr series and arm bases diverging at a 

 relatively small aiigle so that the lower part of the animal appears 

 conical. 



CHARITOMETRA, p. 226. 



C'' genital pinnules evenly, and only slightly, expanded. 



d' more than ten arms ; division series and arm bases rounded dorsally. 



PACHYLOMETRA, p. 215. 



d' ten arms; division series and arm bases subcarinate. 



CHLOROMETRA, p. 225. 



19. — Key to the Subfamilies of ANTEDONiDiE. 



a' Centrodorsal large, conical, the cirrus sockets well separated, at least laterally, 

 and arranged in definite columns ; cirri absent froin the interradial portions of 

 the centrodorsal ; the cirri are large and long, with numerous segments. 



ZENOMETRIN^, p. 233. 



a* centrodorsal smaller, rounded conical to hemispherical or even discoidal, the 

 cirrus sockets exhibiting no regular arrangement and usuall.v closely crowded, 

 b' one or more of the proximal pinnules is absent ; the cirri, which have numer- 

 ous segments, shorter distally than proxiniaily, are evenly distributed and 

 closely crowded on a hemispherical or more or less conical centrodorsal. 



PSBOMETBmiE:, p. 232. 



