314 PROCEEDINGS OF THE ACADEMY OF 



men had only a segment or two of the column attached ; but an 

 end view of it, in his diagram, represents it as being rounds while 

 in the form under consideration it is very distinctly pentagonal. 

 As he does not nay that it differs in the form of the column from 

 his P. alteyniatus (which has a decidedl}^ round column), in point- 

 ing out the distinctions between the two, I also infer that it is 

 round in both. In addition to this, Poteriocrinites gracilis of 

 Hall is stated by him to be found only at the base of the Tren- 

 ton limestone, while our crinoid is only known to occur in the 

 middle part of the Cincinnati group. From these facts, and from 

 the usual very restricted vertical range of the species of Crinoidea, 

 I infer that our Cincinnati form is specificall}'^ distinct from the 

 I^ew York species. 



Locality and position. — One hundred feet below tops of hills at 

 Cincinnati, Ohio. Cincinnati group of the Lower Silurian. Mr. 

 C. B. Dyer's collection. 



POTERIOCRINUS (DENDROCRINUS) POLYDACTYLUS, Shumard (sp.). 



nomocrinus polydactylus, Shumard, 18G7. Trans. Acad. St. Louis, vol. I. 

 p. 78, pi. I. fig. 6. 



An examination of good specimens of this species shows that it 

 has the structure of the bod}' seen in Dendrocrinus^ and that it 

 is related to D. Jeivettii of Billings more nearl^^ than to any 

 other of the species known to the writer. 



This is a ratlier common species in the upper part of the Cin- 

 cinnati group at Richmond, Indiana. 



GLYPTOCRINUS DYERI, Meek. 



Body globular-subturbinate, being wider than high, with sides 

 rounding under to the base. Sub-basal pieces obsolete, or, if pre- 

 sent, not exposed externally. Basal pieces (subradials of some) 

 very small, and projecting as a thin rim below, much wider than 



differ specifically from our crinoid ; but if either a Poteriocrinites proper, or 

 a Dendrocrinus (if we view the latter as only a subgenus oi Poteriocrinites, 

 as Prof. Hall has since done in describing other species), then the name 

 P. gracilis could not stand for the New York fossil, because Prof. McCoy 

 had used that specific name for a species of this genus from the Carbo- 

 niferous rocks in 1844. For this reason, D'Orbigny proposed the name 

 P. subgracilis for the New York species, which will have to be retained if 

 it belongs to any mere section of that genus. 



[February 13, 



