182 C. Wachsmuth—Structure of Paleozoic Crinoids. 
though it is probable that Hugentacrinus and several allied gen- 
era had that summit structure. In the Apiocrinide and 
contrary is covered by a soft peristome. Both are closely 
related to Apiocrinus ; Belemnocrinus particularly has the same 
heavy. body plates and the small viscera] cavity, and it appears 
to me that Apiocrinus is more nearly allied to the Paleozoic 
type than to the recent Rhizocrinus. | 
The Cupressocrinide and Cyathocrinide are the only groups 
from Paleozoic formations which Roemer places in his division 
a. Dr. Schultze, who adopted Roemer’s classification, included 
in the Cupressocrinide the genera “* Synbathocrinus Phill. and 
Phimocrinus L. Schi.,” in which he is undoubtedly correct, for 
se two 
covering of the central opening of Synbathocrinus resembles 
ina remarkable degree that of the central aperture of the Blas- 
