DISCOVERY OF THE DISK OF ONYCHOCRINUS 485 



Professors Waagen and Jahn, in Vol. VII of the Silurian System 

 of Bohemia, have described a new genus, Cakidocrinus, from Stage 

 d 4 of the Bohemian section, which they place near the Taxocrinidae 

 of Angelin, and which Mr. Bather^ assigns to the Flexibilia Impinnata> 

 and considers to be "a genus that approaches the common ancestor 

 of Ichthyocrinus and Taxocrinus." Through the kindness of Pro- 

 fessor Jahn, who made a special trip to the locality near Zahoran for 

 me, I have been favored with some specimens of C. multiramus 

 in as good condition as they are usually to be obtained. They occur 

 in a schist, and all specimens thus far found are so flattened by pres- 

 sure that none of them show all five rays, and I doubt if it is certain 

 whether the anal side is distinct or not. The condition of preserva- 

 tion is such as to render observation on some points very uncertain, 

 Messrs. Waagen and Jahn^ say of this: 



The skeleton and elements constituting the body of these sea lilies are changed 

 into a ferric hydrate. By reason of this change there exist only the negative 

 impressions of half the calyx, which are filled with a powder of ferric hydrate. 



They state that the figures on Plate 63 are very defective, and they 

 give other figures in the text, partly of the same specimens and partly 

 from better specimens. Even of these text-figures, however, they say 

 on p. 109: 



The preservation of the interradius {ir, Figs. 276 — 316 of the text), and of 

 the anal interradius (a, Figs. 276-316 in the text), is so defective that if we can, 

 in some cases, observe the position of the plates which compose them, it is never 

 possible to determine their number. 



1 have six good specimens in the condition described by the 

 authors, viz., impressions in the matrix filled with powder of iron 

 oxide; and one rather larger than usual in which, by rare fortune, 

 the skeleton of the Crinoid is preserved intact. I have also wax 

 casts of the specimens from which Figs. 1-2 and 11-14 of Waagen 

 and Jahn's work were made, kindly sent to me by Professor Dr. Perner, 

 of the Royal Museum at Prague. In none of these have I been able 

 to identify satisfactorily any interbrachial (interradial) or anal plates. 

 Not having seen all the specimens on which the figures are based, 

 I do not deny the existence of such plates; but I wish to suggest 



^Annals and Magazine oj Natural History, July, 1900, p. 112. 



2 Op. cit., p 107. 



