394 PROCEEDINOS OF THE ACADEMY OF [1881. 



Doubtful Genera. 



The following genera, which evidently belong to the Sphreroicl- 

 oerinida?,aretoo imperfectly defined to be grouped systematically. 



1. (?) CONDYLOCKINTIS Eichwald. 

 1860. Eichwald. Letbfea Rossica, i, p. 612. 



From Eichwald 's description , it is impossible to get a correct 

 understanding of this genus. He describes it as having ten 

 basals, three radials, two rows of plates placed above the 

 radials, and numerous other little plates irregularly arranged ; 

 the plates tumid, and the calyx covered with a membranous 

 integument (?). 



From Eichwald's figure, we are inclined to place the genus with 

 tlie Rhodocrinida?, perhaps in the neighborhood of Thylacocrinus, 

 provided we are right in supposing that it has five small under- 

 basals within the ten so-called basals. We take the ten latter, which 

 are said to be tumid, as representing five basals alternating with 

 the five first radials. There are 3 x ^ primar}-, and evidently 

 two rows of secondary radials, separated by numerous interradial 

 and perhaps interaxillary plates. 



Eichwald has referred to it a single species : — 



1860. Condylocrinus verrucosus Eichwald. Lethaea Rossica, p. 612, PI. 31, fig. 51. 

 Silurian. Russia. 



2. (?) SCHIZOCEIiniS Hall. 



1847. Hall. Palseont. New York, i, p. 81. 



1879. Zittel. Handb. der Palseont., i, p. 371 (Stelidiocrinidae). 



The genus was founded upon very imperfect material, but 

 evidently occupies a position near Glyptocrinus, if not identical 

 with it. It probabl}'^ had, like that genus, small or rudimentary 

 underbasals hidden by the column. 



Hall describes it with five pelvis plates (our basals) ; 2 X 5 

 costals (the first and second radials) ; 1 X 5 scapulars (the third 

 primary radials J ; 1 X 5 brachials or arm plates (according to figure 

 a fourth series of primary radials, but probably longitudinally 

 divided, and represented by two plates forming the first series of 

 secondary radials ) ; and above these a double cuneiform arm plate 

 supporting the hand and fingers, we should say a second series of 

 secondary radials, which support the primary arras. 



