1879.] NATURAL SCIENCES OF PHILADELPHIA. 347 



arm pieces are less than half the width of the last, and like all 

 others composed of a single series of joints. 



In the extraordinary width of the lower portion of the arms, 

 the flatness of the arm pieces, and the fact that these lie side by 

 side, abutting laterally, Bursacrinus somewhat resembles Ichthyo- 

 crinus, but tlie arms are comparatively longer and the general 

 construction of the hody otherwise is very distinct. 



Only two species are known ; both are from the Subcarboniferous. 



1861. Bursacrinus Wachsmuthi Meek & Worthen. Type of the subgenus. Proo. 



Acad. Nat. Sci. Phil., p. 137; Oeol. Rep. 111., vol. iii. p. 479, pi. 17, fig. 6. 

 Upper Burlington limest. Subcarb. Burlington, Iowa. 



1862. Bursacrinus confirmatus White. Proc. Bost. Soc. Nat. Hist., vol. ix. p. 11. 



Lower Burlington limest. Subcarb. Burlington, Iowa. 



C. Subgenus (?) PHIALOCRINUS Trautschold. 1 (Not Eichwald ) 

 1879. Monogr. Kalkbrucke von Mjatsckkowa, p. 122. 



Prof. Trautschold proposed the above name in a full generic 

 sense for two species of Crinoids from the Upper Subcarboniferous 

 of Russia. The resemblance to Graphiocrinus, as already men- 

 tioned, is so close that we doubt whether the group can be 

 upheld even subgenerically. So far as known, Phialocrinus patens 

 differs from Graphiocrinus, as now revised, only in having two 

 brachial pieces instead of one, and in the underbasals, which here 

 project slightly beyond the column. The latter is unimportant, 

 and a comparison will show that the two brachials combined have 

 exactly the form of the single plate in Graphiocrinus; their 

 division involves no structural change, but merely facilitates arti- 

 culation. Trautschold's first species only can be placed here: 

 his P. urna is certainly a Poteriocrinus, as indicated by its ob- 

 conical form, the large underbasals, and especially by the arrange- 

 ment of its anal plates. 



1879. Graphiocr. (Phialocrinus) patens Trautschold. Monogr. d. Kalkbriiche 

 von Mjatsch. , p. 123, pi 15, fig. 4. Upper Subcarb. Near Moscow, Russia. 



16. WOODOCRINITS De Koninck. 

 1854. Recherch. Crin. Belgique. Supplement, p. 4. 



General form including arms short and robust; calyx depressed, 

 arrangement of the plates in the anal area unsymmetrical. 



Underbasals five ; small, quadrangular, forming a pentagon 



1 Eichwald's genus Phialocrinus (Lethaea Rossica, i. p. 578, pi. 31, fig. 

 27) was not defined, being founded on fragmentary pieces of column. 



