1890.] NATURAL SCIKNCKS OF PHILADELPHIA. 391 



PLATE IX. 



Fig. 1. Ventral disk of Cyathocrinus alutaceus Angl. 



The orals in lateral contact, and covering nearly the whole 



ventral surface. Refigured from the type specimen in the 



Zool. Riks Muset at Stockholm (Iconogr. Crin. Suec. PI. 



XXIII, fig. 11). 

 Figs. 2 and 3. Ventral disk of Cyathocrinus laevis Angl. 



Fig. 2, specimen in which the orals are partly resorbed. 



Fig. 3, another specimen, in which the orals are replaced 



by large covering pieces. 



From the same Museum (Iconogr. PI. XXVI figs. 2 and 3b). 

 Figs. 4 and 5. Ventral disk of Euspirocrinus spiralis Angl. 



The orals replaced by large ambulacral plates uniting in 



the center. 



(Same Museum, Iconogr., PI. IV, figs. 7d and 7e). 

 Fig. 6. Ventral aspect of a specimen of Cyathocrinus 



gilesi W. and Sp. 



The " consolidating plates " in part covered by small per- 



isomic pieces ; the ambulacra not preserved. 

 (Collection of Wachsmuth and Springer). 

 Fig 7. Ventral disk of Cyathocrinus brevisacculus W. 



and Sp. (n. spec). 



Showing the " madreporite." The oral center closed by 



the fused covering and side pieces ; the " consolidating 



plates " partly exposed. 

 (Same collection). 

 Fig. 8. Ventral disk of Cyathocrinus nodosus W. and Sp. 



(n. spec). 



Showing the " madreporite," the ambulacral and interam- 



bulacral plates. 

 (Same collection). 

 Fig. 9. Ventral aspect of a very y^oung specimen of Cy'a- 



THOCRINUS brevisacculus. 



The orals partly intact. 

 (Same collection). 

 Fig. 10. Ventral aspect of the type of Marsupiocrinus de- 

 PRESsus Angl. 



Specimen in the Zool. Riks Muset at Stockholm (Icono- 

 graph. PI. X, fig. 16). 



