1879.] NATURAL SCIENCES OP PHILADELPHIA. 319 



Column round, undivided longitudinally (except in V. dilata- 

 tus)', central perforation scarcely of medium size. 



This genus occupies a position S3 r stematically between Cyatho- 

 crinus on the one side and Botryocrinus and Barycrinus on the 

 other. It differs from Barycrinus in the delicacy of its body plates, 

 in having two brachials instead of one, in the less robust arms, 

 and in having a round column with a comparatively small and 

 simply constructed passage, in contrast to the pentagonal, divided 

 column, and wide and complicated central canal of that genus. 

 From Botryocrinus it differs in the form of the ventral sac and 

 the construction of the arms. 



Geological Position, etc. Devonian and Subcarboniferous ; only 

 found in America, save one doubtful species from the Eifel. 



The following species are considered as belonging here : 



#1866. C?)Vasocrinus dilatatus Schultze. (Potericr. dilatatus, not Hall = Coe- 

 liocr. dilatatus.) Mon. Echinod. Eifl. Kalk., p. 49, pi. 5, figs. 3, 3 a. De- 

 vonian. Eifel, Germany. 



This species has the column divided longitudinally, and therein 

 approaches Barycrinus, from which it differs in having thin body 

 plates, and a form exactly as in Lyon's typical species V. valens. 



*1861. Vasocr. Lyoni Hall. (Cyathocrinus Lyoni.) Type of the genus. Desc. 

 New. Pal. Crin., p. 5; Bost. Journ. Nat. Hist., p. 298. 1868. Meek & 

 Worthen. Barycrinus Lyoni. Proc Acad. Nat. Sci. Phila., p. 340. 

 Keokuk limest. Subearb. Crawfordsville, Indiana. 

 Syn. Cyathocrinus hexadactylus, Lyon & Casseday. 1859. Amer. Journ. 

 Sci., p. 74. 



Lyon's name has precedence, but being specifically as well as 

 generically incorrect (see note above), we adopt Prof. Hall's later 

 name. 



#1861. Vasocr. macropleurus Hall. (Cyathocr. macropleurus.) Desc. New. Pal. 

 Crin., p. 5; Bost. Journ. Nat. Hist., p.. 295. Meek & Worthen, Scaphiocr. 

 macropleurus. Geol. Rep. 111., vol. v. p. 412. Lower Burl, limest. Subearb. 

 Burlington, Iowa. 



1857. Vasocr. sculptus Lyon. Geol. Rep. Ky., vol. iii. p. 486, pi. 4, figs. 3 b-e. ; 

 Hall, 1877. Cyathocr. sculptus. Pal. N. Y., vol. v. (advance sheet No. 2) 

 p. 6. Hamilton Gr., Devonian, above Hydraulic Bed. Jefferson Co., Ky. 



1857. Vasocr. valens Lyon. Geol. Rep. Ky., vol. iii. p. 485, pi. 4, figs. 3, 3 a. 

 Hall, 1877. Cyathocr . valens. Pal. N. Y., vol. v. (advance sheet No. 2) 

 p. 6. Hamilton Gr. Devonian, above the Hydraulic Bed. Near Green- 

 ville, Ky. 



