Mr. V. A. Bather o?i British Fossil Crinovh. 383 



a tree that follows out the descent of individuals. To repre- 

 sent this in convenient classificatory form is the final problem. 



First there is a group which one feels almost inclined to 

 remove entirely from the Fistulata, viz. the Hybocrinid^e ; 

 the ventral sac of Hybocrinus and Hybocystis, in which 

 genera alone it has been observed, is very small, and its truly 

 fistulate nature doubtful*. 



There are next two main groups, one of which includes 

 the families Heteroc'RINID^ (to which I add Anomalocrinus) , 

 Calceocrinid^, and CatillOCRINID^E. So far the families 

 are very nearly the same as those maintained by Messrs. 

 Wachsmuth and Springer. 



The second group, which comprises all the Dicyclic and 

 two Monocyclic forms, must be again split up, and here a 

 rather different arrangement from that of previous writers seems 

 inevitable. 



First comes a Division characterized by brachianal, large 

 radianal, and usually some other anal plates in the dorsal 

 cup, and by clichotomous arms. This can again be divided 

 into three ; on one side a Family including Garabocrinus and 

 T/ienarocrinus, hut of this 1 am doubtful; on the other a 

 Family of Eiisjrirocrinas and its descendants, and in the 

 middle a Family continuing the main line through Dendro- 

 crinus: this is conveniently split into two Series marking 

 the development of pinnules ; Series 1. may be called 

 Dendrocrinites, Series 2. Scaphiocrinites. The Family itself, 

 which will include Merocrinus and Otlawacrinus } may be called 

 Dendrocrinid^e. 



The next great Family starts from Botryocrinus } and this 

 again must be split into series ; the Botryocrinites will include 

 all in which the radianal is rudimentary, and pinnules as a rule 

 not yet evolved from armlets ; the Scytalecrinites will include 

 Decadocrinus and Scytalecrinus, both of which are elongate 

 (a/cvTaXyi)) have three anal plates in dorsal cup, and have 

 pinnules ; the Graphiocrinites will include genera in which 

 the radianal is lost but in which the brachianal remains in 

 the limits of the dorsal cup ; the Erisocrinites of Wachsmuth 

 and Springer may remain, or may be included with the En- 

 crinites, as comprising genera in which no anal plate remains 

 in the dorsal cup of the adult ; the Cromyocrinites will include 

 the rounded forms in which the three anal plates are retained 

 in the cup. In allusion to the ten arms borne by all genera 

 of the Family, the name Decadocrinid^e may be fitly applied 

 to it. 



* \V. & S. Rev. III. (199, 200) Proc. 1886, p. 123. 



