8 PEOCEEDINGS OP THE NATIONAL MUSEUM vol.74 



tentatively referred to Vasocrimis, but their ascription to the genus 

 is not sufficiently certain to warrant their description in this paper. 



JaekeP has proposed the new genus CostalocHnus with Poterio- 

 crlnus dilatatus L. Schultze as the genotype. C ostalo(ynnus dila- 

 tatus does not have rt in the dorsal cup, but otherwise greatly re- 

 sembles Vasocrinus. Among the described crinoids of the German 

 Devonian, two species I think are certainly referable to Vasoerinm. 

 These are Poster iocrinus steUaris L. Schultze and PaHsocrinus 

 canaliculatus Jaekel. It is of interest to note in this connection 

 that the type of Vasocrirms stellaiis (Schultze) has no rt, but a speci- 

 men considered by Jaekel as undoubtedly conspecific has three anal 

 plates in the cup. Vasocrlnus canaliculahis (Jaekel) appears to be 

 very close to the typical form of Vasocrinus. 



Generic diagnosis. — Dorsal cup subturbinate to somewhat bowi- 

 shaj)ed. Plates relatively thin. Radials curving inward in their 

 upper portions, forming a marginal platform around the periphery of 

 the tegmen, except in the posterior interradius. Arm facets broadly 

 horseshoe shaped, with the axial canal typically sej)arate from the 

 food groove. There is a tendency toward the suppression of the food 

 groove in the anterior radius. Arms stout in their proximal portion, 

 horizontally disposed or somewhat inclined upward. Judging by the 

 articular facets, the arms were capable of considerable movement 

 upward. Three anal plates within the cup, RA, x, and rt, supporting 

 a stout ventral sac. The tegmen is low, composed in the main of small 

 plates, and a madreporite is probably present. The stem is round and 

 pierced by a pentagonal or pentalobate canal. The ornamentation of 

 the cup consists of series of folds radiating from the centers of the 

 plates. 



Horizon. — So far as known, Vasocrinus is restricted to the Middle 

 Devonian. 



Genotype. — The genotype is Vasoa^mis valens Lyon. 



VASOCRINUS VALENS Lyon 



The description of this species is based on the original specimens of 

 Lyon's Figures Za and 3&, supplemented by three imperfect dorsal 

 cups from the type locality. 



Lyon's type specimen, Figure 3a, gives the following measurements : 



Height of dorsal cup, 14 mm. 



Diameter of dorsal cup, 25 mm. ± (estimated). 



Diameter of stem, 9 mm. 



Heiglit of IBB, 3.5 mm. 



Height of BB, 7 mm. 



Width of BB (average), 0.4 mm. 



3 Jaekel, Otto, Phylogenie und System der Pelmatozoen. Paleont. Zeitsclir., vol. 3, 

 Heft 1, p. 61, 1918. 



