52 ECHINODERMA OF THE INDIAN MuSEUM, PART VII. 



li* none of the lower pinnules stiffened and spine-like ; the enlarged 

 lower pinnules have at least 20 segments and are flagellate 

 distally ; no ventrolateral processes on the division series, 

 i' P| greatly elongated, much longer than the very short 

 succeeding pinnules; division series very widely separated. 



(O) rONTIOMETBID^, p. 138. 



{Cj. key 12.) 



i^ Pi shorter than the succeeding pinnules ; division series 

 usually in close lateral apposition. 



(0) MARIAMETBID/E, p. 139. 



(Cj. key 13.) 

 b* lIBr 4 (3+4). 



c' oral pinnules long and slender, composed of very numerous short seg- 

 ments and bearing a comb distally ; mouth usually marginal to sub- 

 central ; anal tube usually lateral. 



(O) COMASTERIDiE, p. 68, 



{Cf. key 7, 8.) 



c' oral pinnules smooth distally, without a comb ; mouth always central ; 

 anal tube lateral. 



d' elements of the IBr series united by pseud o-syzygy . not differing exter- 

 nally from a true syzygy. 



(O) ZYGOMETRID/E, p. 9'J. 



{Cf. key 9.) 



d* elements of the IBr series united by synarthrv. 

 e' all the pinnules sharply triangular or prismatic, rather stout, the outer 

 with comparatively short segments which do not have swollen articula- 

 tions ; pinnule ambulacra bordered with well-developed side and 

 covering plates. 



f Pj very delicate, flexible, and weak, the flrst two segments enlarged, 

 the remainder very short and squarish ; disk globose, compact, 

 entirely enclosed by a solid pavement of small plates ; muscular 

 fossaj on the articular faces of the radials transversely linear. 



(O) CALOMETRID^, p. 177. 



(Cy. key Hi.) 



f'^ P^ longer than, or resembling P, ; ventral surface of disk slightly 

 concave, studded with scattered calcareous plates which rarely 

 form a complete pavement ; muscular fossa* on the articular faces 

 of the radials high, much higher than broad, and narrow, 

 g' cirri comparatively slender, with more than 25 segments, of 

 which the distal are short and bear dorsal spines ; Pj usually much 



