282 PROCEEDINGS OF THE AMERICAN ACADEMY 



33. HOOKERIA Wrightii (sp, nov.) : dioicum, majusculum, pros- 

 tratura, dense pinnatim ramulosum, subcompresse foliosum ; foliis 

 oblongo-ovalibus subito in acumen longum tenue flexuosum productis, 

 marginibus infra acumen convolutis, cellulis angustissime linearibus, 

 costis binis ad medium evanidis ; capsula oblonga ingequali macrostoma 

 inclinata ; peristomio normali eciliolato ; operculo convexo-conico recte 

 rostrato ; calyptra e basi mitriformi multifida longe rostrata. 



Growing with Hypniim Ometepense. 



The following paper was also presented through the Corre- 

 sponding Secretary. 



A Synonymic List of the Echinodermata of the Palaeozoic 

 Rocks of North America. By S. S. Lyon and S. A. 



Casseday. 



In devoting the leisure hours of the last few months to the study of 

 the Crinoidea of Kentucky and other of the principal Western States, 

 we found, at the very outset, that the principal difficulty attending such 

 researches was the entire absence of any concise summary of the 

 labors of American paheontologists among this interesting family of 

 fossil remains. In order to supply this deficiency, the following syno- 

 nymic list was formed for our private use ; but, hoping it might aid 

 others engaged in similar studies, it was determined to offer it for pub- 

 lication. It embraces only the Crinoidea of the Palteozoic Rocks ; as 

 our acquaintance with those of the newer systems is necessarily exceed- 

 ingly limited, owing to their imperfect development in the States to 

 which reference has been made above. Besides, the rocks above the 

 Permian afford comparatively few species of these organisms. 



It was at first intended to divide the subcarboniferous into upper 

 and lower ; but the imperfect knowledge of the stratigraphy of the 

 Western rocks precludes the feasibility of such a division. 



These labors have been retarded, and possibly left imperfect, on ac- 

 count of the few facilities within our reach. Unable to command an 

 extensive collection of authorities, we have been forced to gather here 

 and there, in private libraries, the required information. 



Some of the species recognized in the table were evidently founded 

 upon mere fragments, which, however interesting in themselves, are 

 wholly insufficient for characterizing species. They are enumerated, 

 however, in order that the table may be as complete as the materials 

 within reach would allow. 



