304 PROCEEDINGS OF THE ACADEMY OF [1879. 



long, composed of wedge-form plates, which give off on alternate 

 sides a row of strong pinnulae, such as are found in Poteriocrinus. 

 The specimen shows one side and partly the anterior of the body, 

 for the ray at the extreme right has apparently more brachials 

 than the other four, which is a very common occurrence in Pote- 

 riocrinus. Anal plates are not visible in the specimen, being 

 probably imbedded in the rock. The second specimen, Fig. 28, 

 is not sufficiently intelligible. The posterior side is shown, but 

 the arrangement of the anal portion is so obscure that it gives no 

 information whatever. The form of the calyx is like Poteriocri- 

 nus, subcorneal, and resembling Fig. 1. 



The third specimen, Figs. 29 and 30, from the Ashmolean col- 

 lection of Oxford, gives only the calyx, but this is sufficient to 

 show that it is an entirely different form from that represented by 

 Figs. 1 and 28. The position of the plates, the form of the catyx 

 with strongly convex sides, the peculiar articulating facet of the 

 first radials, their proportions, and the arrangement of the anal 

 area, agree in every respect with Miller's generic diagram, 1 and 

 with those species which we have mentioned as having no pin- 

 nulae. On the other hand, the first two figures in the subconical 

 form of the calyx, in the disposition and form of the plates, in 

 having two additional brachials in the anterior ray, in the presence 

 of pinnula?, closely resemble Poteriocrinus. This has induced us 

 to consider the Ashmolean specimen alone 2 to be Cyathocrinus 

 'planus and the type of the genus, and we propose an amendment 

 of the generic formula so as to admit only those species that are 

 without pinnulae, making the latter one of the best distinctions 



1 Miller's diagram of the Ashmolean specimen, Fig. 30, appears at first 

 sight to be very different from the generic diagram of the preceding plate, 

 but it must be understood that the four small plates, arranged in the figure 

 in a half circle, are to represent the interradials (oral plates) in the dome, 

 and not the plates of the ventral sac, as might be expected. 



2 We were not aware, when the above was written, that Austin, who ex- 

 amined most of Miller's original specimens, came to almost the same con- 

 clusion in regard to C. plaints (Rec. & Foss. Crin., p. 2). He remarks that 

 Miller in some cases has taken " parts of different animals and jumbled them 

 together" to render his figures as perfect as possible, and on page 59 he 

 says: " Miller's principal figure of the C. planus cannot be depended on, 

 as he appears to have taken the rays of Toxocritius longidactylus and placed 

 them on the body of G. planus." In supposing these to be the arms of 

 Taxocrinus, Austin is certainly mistaken. 



