190 



THE CRINO1DEA 



(1876, based on Dimerocrinus oligoptilus, Pacht ; probably includes Aristo- 

 crinus or Callawaycrinus, Rowley, 1895), Silurian (?) and Devonian, 

 N.-W. Europe and N. America ; iBr few, proximal large ; x rests on large 

 truncate post. B, a little to the right, and supports numerous smaller 

 plates in somewhat irregular vertical series ; the IIIBr rami bear ramules 

 on the sides towards the middle of the dichotom, the proximal raruule 



branches again (Fig. CX. 4). 

 Synerocrinus, Jaekel (1897), 

 Carboniferous, Europe, has arms 

 like Dadylocrinus, except that no 

 ramules branch ; it also differs in 

 having 3-8 iBr, perhaps more, with 

 occasional illBr and illlBr ; y rests 

 on post. B (Figs. CX. 5, and CXI.). 

 This genus probably includes the 

 Belgian species erroneously referred 

 by de Koninck to Taxocrinus nobilis 

 when erecting Forbesiocrinus. Euryo- 

 crinus, Phillips (1836), Carboni- 

 ferous, England, is probably a close 

 ally, but its anus are not well 

 known. Onychocrinus, Lyon & 

 Casseday (1859), Carboniferous, N. 

 America and Ireland, has a large 

 proximal iBr followed by small 

 plates, often numerous, merging 

 with the tegmen and ventral cover- 

 ing of the arms, but leaving the 

 arms more free than usual in the 

 sub-order ; I IBr rami bear branch- 

 ing ramules, either along each side 

 or in clusters at end, but the 

 heterotomy is always bilateral, not 

 MUS. unilateral as in all the genera just 

 mentioned a fact suggesting that 

 Onychocrinus should form a distinct 



basal is .just visible on the left; dl, fossa for V fT T 



dorsal ligament ; mf, muscle-fossa ; pt' , surface (see also Fig. XVII. 4). 



FIG. CXI. 



Synerocrinus incurvus, from Brit. 

 E6707. 1, from the right anterior side, x J. 

 2, joint-surface of a brachial, x 3 diam. 3, a 

 radial, showing articular surface for ttrst primi- 



brach, and on either side the surfaces of loose r .. , , . .. 



suture with interbrachials, x i!. B, basais, family or, at least, Bub-family (Fig. 

 which pass umler the cup, the larger posterior CX g) . analg 3.5 rest i ng on post g 



FAMILY 5. 



SAGENOCRINIDAE. Impinnata with 

 over 20 iBr, 6 or more illBr, and 



variable number of illlBr; arms isotomous or almost so, to VIBr 

 or beyond ; anals not a distinct series, but represented by greater width 

 or number of iBr in post. IR. Genera Sagenocrinus, Austin (1843), 

 Silurian, Europe and N. America, has RA sunk between post, and 

 r. post BB, so that proximal iBr is supported between post. B and RA 

 (Fig. XXIVa). In " Forbesiocrinus Agassizi" Carboniferous, N. America, 

 which may be placed in this family, post. B supports 2 iBr, and there 

 are considerably more iBr in this IR Patelloid plates are richly 



