FOSSIL CRINOIDS. 147 



name subaequalis of Wachsmuth and Springer will follow Scaphiocrinus into the 

 synonymy. As this species is to be found in all the principal collections where 

 Crawfordsville Crinoids have been sent, I suggest to those in charge that they 

 change the label for it to that above indicated. There is a good figure of the 

 species in Hall's photographic Plate V (N. Y. St. Cab. Bull. I, fig. 10, privately 

 distributed) ; also one of a very mature specimen in Report of the Geological 

 Survey of Illinois, V, PL XV, fig. 6. And the two species described by Dr. 

 White in 12th Kept. U. S. Geol. Surv. for 1878 (1880), p. 161-2, PI. XL, figs. 3a 

 and 4a, as Scaphiocrinus gurleyi and »S. gibsoni, are synonyms of it. 



This will also require the removal from Woodocrinus of all the species trans- 

 ferred to it by Wachsmuth and Springer from Pachylocrinus (Rev. Pal., Ill, 242) ; 

 but will leave under that genus provisionally the following American species, 

 mentioned on the same page as transferred from Zeacrinus, viz : — Poteriocrinus 

 bursaeformis White; Zeacrinus elegans and Z. ramosus of Hall; Z. scobina, 

 Z. serratus and Z. iroostanus of Meek and Worthen; to which nmst be added 

 Z. commaticus S. A. Miller. All of these are distinguished from Pachylocrinus 

 by having quadrangular brachials, and a more heterotomous arm arrangement; 

 which, however, the typical Woodocrinus does not possess, and the above named 

 species will probably have to go into a new genus. 



With these explanations, intended, as already indicated, only to clear up a 

 few doubtful matters needing adjustment, and not at all as a general discussion 

 of the group, I think the following may be taken as a working basis for a manage- 

 able arrangement of the genera composing the family Poteriocrinidae : — 



Analysis of the Genera. 

 Radianal 



Radial facets round, not filling face of R. 



Rays dichotomous, branching frequently beyond 



IIBr. Ventral sac large and long Poteriocrinus. 



Radial facets straight, filling face of R. 



Rays branching frequently beyond IIBr. 

 Arms dichotomous 



Brachials cuneiform 



Ventral sac strong Pachylocrinus. 



Brachials quadrangular 



Ventral sac not conspicuous Woodocrinus. 



Arms heterotomous 



