1895.] 



ME. P. A. BATHBK OH UINTACRINTTS. 



1001 



mucli tbe same thing occurs in the Pentaerinidse and Apioerinidse. 

 If Dachcrinus, or an allied form, is the ancestor of Peatacrinus in 

 one direction, of Apiocrinus in another direction — then why not 

 of Uintacrinus in a third direction ? As to the loss of the stem, it 

 may have been by a process of gradual dimiuutioa, or in conse- 

 quence of a habit of sudden sepai-ation. In favour of the former 

 view are the instances of mauy species of Pentacrums, which are 

 known to move from place to place, and especially of Miller icri mis 

 ])ratti, the stem of which gradually dwindles to nothing. In favour 

 of the latter view is the suggestive fact that in the slabs of fossil 

 Dadocrinus the crown is almost always brolien off from the stem 

 either at, or immediately below, the junction of the stem with the 

 cup ; and this must have taken place as a reflex response to some 

 stimulus rather than as the result of force, for the crowns are 

 otherwise undistui'bed, and are still in natux-al juxtaposition with 



outer, then on the inner side, and so on regularly. One variation shows syzy- 

 gies between secundibrachs 1 & 2, 3 & 4, 5 & 6. Another shows syzygies between 

 secundibrachs 1 & 2, 3 & 4, 5 & 6, 8 & 9. Professor von Koenen has obliged 



Fig. 13. 



Dadocrinus gracilis, portion of a specimen from Sacrau, near Gogolin in Silesia, 

 Brit. Mus. E 6070. The drawing shows basals, radials, primibrachs, 

 secundibrachs (or distichals), pinnules, and interbrachials. Magnified 

 5 diameters. 



me by examining his numerous specimens with reference to this point, and 

 admits that such differences from his own account do occur. He is at variance 

 with me only in considering them "anomalous;" but there is nothing really 

 anomalous about them, for the law of alternate pinnulation is never abrogated. 

 The only question is, which type is the most usual. The one Von Koenen finds 

 most often, I find most seldom. Both, however, agree with Uintacrinus so far 

 as they go. 



