160 Cincinnati Society of Natural History. 



Locality and Position — Pulaski couiit}^, Kentuck}^, from the Kas- 

 kaskia (Chester) Group. Sub-carboniferous. Three specimens. 



Remarks — This beautiful and curious species has been referred to 

 Cromyocrinus^ not without great hesitation. Among the divisions of 

 Poteriocrinus established b}^ Wachsmuth and Springer, their Decado- 

 crinus most nearly embraces the characte;:s of this species. But the 

 description reads, "arms always ten." It differs from typical Poterio- 

 crinus in the arrangement of the azj^gous plates, in the great thicken- 

 ing of the radials and brachials, the few joints of the arms, and the 

 enormous development of the basal on the az3^gous side. All these 

 features ally it to Cromyocrinus or Eupachycrinus, from which it 

 differs in the greatly developed ventral sac, the few arm joints, and 

 the comparatively short arms. 



Mr. Wachsmuth, to whom I sent the species, after writing as follows : 

 " This is one of those x^erplexing t3^pes which occur at the end of the 

 sub-carboniferous, in which the characters shade from one genus to an- 

 other by transition forms," refers it with some hesitation to Poterio- 

 crinus, 



In this reference he has the confirmatory evidence stated above. To 

 my mind, however, the weight of evidence is in favor of a reference to 

 Cromyocrinus^ Trautschold, which Mr. Wachsmuth regards as a s}^- 

 onym of Eupachycrinus. The surface of this species to the second 

 radial series is ornamented with numerous irregularly disposed tu- 

 bercles; above this the second radials and arm plates are ornamented 

 with slightly raised longitudinal ridges. - 



This crinoid has a very high interest, as one of those t3^pes to which 

 attention was first called by Mr. Wachsmuth, embracing " transition 

 characters," and occurring at the end of a long series of differentiations. 



