LECANOCRINIDAE 1 53 



some fragments in the Riks Museum (PI. VI, fig. 15&). The dorsal cup is broken off just 

 below the axillary primibrachs, and thus the inner surface of the disk is thoroughly exposed. 

 The teginen is constructed as usual in the Flexibilia, consisting of a plated integument, with 

 five orals surrounding an open central space from which the ambulacra pass out between the 

 orals to the arms. Two of the ambulacra and all the orals are well preserved, as is also the 

 interambulacral integument. This structure is in every substantial particular the same as that 

 in Taxocrinus discovered and described by Wachsmuth and Springer nearly 30 years ago. 



The type represented by these two genera was not of long duration, as nothing like it is 

 known later than the Silurian in which it appeared. It was evidently also much restricted 

 geographically, not having as yet been recognized in America, where so many other of the 

 rare and specialized Swedish genera are now known to occur. P2ight species have been recog- 

 nized, of which three are placed under Hoir.alocrinus and five under Calpiocrinus. They 

 may be arranged as follows : 



The Species of Homalocrinus 



I. Arms in 10 main rami, bearing ramules. 



Ramules simple, gradually diminishing. 



Crown ellipsoid ; iBr in one series H. parabasalis. 



Lower ramule branching, much enlarged. 



Crown subglobose ; iBr in more than one series above first H. liljevalli. 



The Species of Calpiocrinus 



II. Arms in 20 main rami, bearing ramules. 



Inner arm of dichotom less developed than outer. 

 Post. B angular, not touching anal .v. 



iBr in two series above the first C. intermedins. 



Post. B truncated by anal x. 

 iBr in one vertical series. 



Crown ovoid C. ovatus. 



Crown oblong C. heterodactylus. 



Main rami equal. 



Post. B truncate. iBr in vertical series. 



Crown ellipsoid, plates uneven, convex C. ftmbriatus. 



Crown ovoid, plates evenly curved C. rotundatns. 



Insertae sedis 

 ( ?) Homalocrinus pecidiaris Plate VII, figs. 6a-e. 



