ICHTHYOCRINIDAE 3II 



widening upward; IIIBr short and wide, plates diminishing regularly in width 

 by steps as ramules are given off at every third or fourth plate. Ramules very 

 small, rounded, having much the proportions of pinnules; lower ramules less 

 than one-third the width of the plates which bear them, those higher in the ray 

 gradually approaching the size of the main arm. There are ten or more ramules 

 in a mature specimen, usually simple ; branching observed exceptionally. Column 

 round, half the diameter of the base outside of the rim; proximal columnajs 

 thin, there being at least three within the basal cavity. 



Not having access to the types or to any other specimens, I have in the description of 

 this species been compelled to rely entirely upon Pacht's figures. These are very elaborate, 

 and bear evidence of great care and skill in the study of the excellent material before him; 

 so much indeed as to induce regret that he did not propose a generic name for this new 

 and distinct type, instead of referring it to a genus with which it has no possible connection. 

 I have made a slight correction in his cross-section of the base (PI. XLI, fig. id), to agree 

 with the present understanding gained from. the study of other species; what he represents 

 as the upper columnal projecting inside the base is clearly the infrabasal ring, just as is seen 

 in the section of Dactylocrinus excaz'atns on the same plate. The large central opening at 

 the inside (fig. ic) is the expanded triangular funnel found in other genera. In the small 

 size and regular form of the ramules, this species is an excellent example of the stage of 

 heterotomous arm-branching which is superficially close to pinnulation ; the intervals consist 

 of two or three brachials in the lower part, but they become shorter toward the distal end of 

 the arm, a fact also observed in other species. 



The species occurs in the lower beds, of the Upper Devonian, associated with Spirifer 

 archaici and Rhynchonella cuboides. The principal type specimen was found at Costijitsi, 

 on the bank of the river Schelon in the government of Pskov, in northwestern Russia. 

 Another used in the illustrations by Pacht was from Isborsk in the same region ; and 

 Wenjukoff in 1886 described and figured still another well-preserved specimen from the latter 

 locality, evidently a much younger individual and differing from those of Pacht in having 

 four IIBr, provided the figure is correct ; it does not afford details enough to be of service for 

 comparison. 



Types. I have not been able to locate the types. 



Horizon and locality. Upper Devonian ; Government of Pskov, Russia. 



Dactylocrinus beyrichi (Dewalque in Fraipont) 

 Plate XLI, figs. 3-4 



Zeacrinus beyrichi Dewalque in Fraipont (Recherch. Crin. Famennien Belgique), Ann. Soc. Geol. Bel- 



gique, XI, 1884, p. 112 with text-fig., pi. I, fig. 5. 

 Taxocrinus beyrichi, Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 3, 1886, p. 144. 

 Dactylocrinus beyrichi, laekel, Zeitschr. d. deutsch. geol. Gesell., for 1897 [1898]. p. 47. 



Specimens of moderate size. Crown elongate, expanding to top of IIBr, 

 where height to width is i to 1.7, spread of calyx, 1 to 3.5 ; cross-section at that 

 level deeply decagonal; side outline slightly curved. Base truncate, more 

 rounded than in D. oligoptilus and without any expanded rim ; sharply excavate, 

 the edge cutting radials and basals, and the cavity deep enough to hold several 

 columnals. Surface coarsely granulose. Crown of largest specimen, 31 mm. 

 high by 25 mm. wide; base, 7 mm., column, 5 mm. 



