144 FOSSIL CRINOIDS. 



First, the genus Scaphiocrinus, which includes a large number of well known 

 species that have gone under this name for nearly fifty years, and is especially 

 conspicuous in the great collections of several leading museums made from the 

 American Lower Carboniferous during the times of Barris, Wachsmuth, Worthen, 

 Gurley, etc. The changes which I have long known must be made are unfortu- 

 nate and vexatious, just the sort of overturning of familiar names that I dislike to 

 see; but there is no help for it. The treatment of this name by Wachsmuth 

 and Springer (Revision of the Palaeocrinoidea, I, 112, 121), in connection with 

 Graphiocrinus, gave form to an idea which leads to a vast amount of trouble. 

 All the species ranged under it by Meek and Worthen, by Wachsmuth and 

 Springer, and their followers, will have to be referred to some other genus. 



Scaphiocrinus was defined by Hall in 1858 (Geol. Iowa, II, 550), with a good 

 diagnosis, a generic diagram, and a species which in a note he expressly declared 

 to be the type, S. sbnplex — a well known species of the Burlington Limestone. 

 All these agree in the following characters : — A single anal plate between the 

 radials; no radianal; 10 unbranched arms (i e., one bifurcation), with parallel 

 joint sutures. On the assumption, suggested first by Meek and Worthen (Geol. 

 Surv. Illinois, II, 181, 238), that this was identical with de Koninck and Lehon's 

 genus Graphiocrinus, we referred Hall's type species, S. simplex, to that genus, 

 and then ranged a large number of Poteriocrinoid species under Scaphiocrinus 

 as a subgenus — afterwards taken as a full genus — all of which have these 

 characters: — A radianal; arms repeatedly branching, with usually more or less 

 wedge-shaped brachials; — an absolutely distinct generic type. This cannot 

 be done under the rules of nomenclature. 



Hall's Scaphiocrinus must stand as defined, with S. simplex as type, unless 

 held to be a synonym of Graphiocrinus de Koninck and Lehon (Rech. C'rin. Carb. 

 Belg., 115) ; and in any event another name must be found for the species placed 

 by us under Scaphiocrinus, which form a good generic group. 



Graphiocrinus, though described by its authors as having basals only, is a 

 dicyclic Crinoid, and the only difference from Hall's Scaphiocrinus simplex is 

 in the supposed position of the anal plate, which is represented in de Koninck's 

 figure as not touching the posterior basal, but resting on the upper corners of 

 the radials, abutting against the first brachials. This is apparently different 

 from the position of this plate in Scaphiocrinus, approaching the arrangement in 

 the later Upper Carboniferous genus Erisocrinus White, in which the anal x has 

 risen entirely from between the posterior radials, and rests on their distal corners. 

 The plate is, however, partly between the radials in de Koninck's figured speci- 



