Clark — New Genera of Unstalked Crinoids. 175 



dorsal containing the chambered organ and overlying structures large; 

 there is no neurilemma; the disk is naked, or studded with minute plates 

 which may fuse into larger iilates in the interradial angles; pinnules all 

 cylindrical or more or less flattened, and slender, and with very long seg- 

 ments; the post-radial series do not divide, or divide })ut once. 



Included families. — Aiitedonkhv ; Atclccyhiidiv ; Fentametrocrinidx. 



The family Comasterid;e falls naturally into the three following sub- 

 families : 



Capillasterinee sub-fam. nov. 



The distal cirrus segments bear dorsal processes; in genera containing 

 species with more than ten arms the arm division is extraneous or com- 

 pound, never interpolated. 



Included genera. — Nemaster ; Capilldster ; Nrocoviatrlla ; Comntella ; 

 Comatilia ; Lcptonemnstcr ; Comissia. 



Comactiniitife suli-fam. nov. 



The cirrus segments are entirely smooth dorsally; the segments of tlie 

 genital pinnules are extremely sliort and more or less produced distally; 

 more than ten arms are rare; when present the division series are inter- 

 polated, and of two ossicles. 



Includeil genera. — Comalula ; Comactinia ; Comiii'ui. 



Comasterinee sub-fam. nov. 



The distal cirrus segments bear dorsal processes; two or more division 

 series are present, always interpolated ; a few at least of the division series 

 always consist of four ossicles. 



Included genera. — Comaster ; Comanthns. 



The family Himerometridic, as previously understood, may be advan- 

 tageously sub-divided as follows: 



Pontiometridae fam. nov. 



Oligophreate comatulids in which the oral pinnules are greatly elon- 

 gated, slender, and flagellate, without combs distally; the mouth is 

 approximately central, the anal tube slender and very long; the articu- 

 lar faces of the radials are entirely and \\idely separated and as dee]) as 

 broad, well rounded; the central canal bisects the transverse ridge dorso- 

 ventrally ; the transverse ridge bears on each side of the central canal a 

 triangular ligament pit which may be called a falcral ligament fossa; 

 there are no muscular foss:e on the radial faces. 



Included genus. — Ponttometra. 



Himerometrinae sub-fam. nov. 



The second division series (usually present) is always of four ossicles, 

 at least in part; the brachials are very, often excessively, short. 



Included genera. — Amphimetra ; Himeroinetra ; Craspedometra ; 

 Heterometra. 



