Messrs. Austin on some new Crinoidea. 195 



XXXIII. —Descriptions of several new Genera and Species 

 of Crinoidea. By Thomas Austin, Esq., and Thomas 

 Austin, Jun., Civil Engineer. 



In deference to the recommendation of the British Association 

 for the Advancement of Science, we have endeavoured, in esta- 

 blishing our new genera and species, to adhere as closely as 

 possible to the rules which have been sanctioned by that 

 body; and though we have experienced considerable diffi- 

 culty in extricating some groups from the confusion in which 

 they were involved, we trust on the whole that our labours 

 will be found to be in accordance with the liberal and en- 

 lightened views propounded by the Committee appointed to 

 report on the means of rescuing the nomenclature of Zoology 

 from the almost inextricable confusion it has fallen into. 



Family Poteriocrinid^e, Austin, 



containing the following genera : Poteriocrinites, Cladocrinites, 

 and Synbathocrinites. 



Genus Poteriocrinites, Miller. 

 The generic characters defined by its founder. 



Sp. P. dudleyensis, Austin, sp. 



Definition. — The plates surrounding the body agree in 

 number and arrangement with the generic character. The 

 upper series or ray-bearing plates are abruptly truncated on 

 their superior edges, which are excavated and have central 

 ridges for the articulation of the rays. These ridges extend 

 the whole width of the plates. The unique specimen examined 

 somewhat resembles P. granulosus in figure, but the dorso- 

 central plates are less dilated ; and it differs from that spe- 

 cies in the absence of granulae, all the plates being quite 

 smooth. Column and rays unknown. 



This is the only instance in which the genus Poteriocrinites 

 has been met with in other strata than the carboniferous lime- 

 stone. The specimen is in the cabinet of J. Johnson, Esq. 



P. isacobus, Austin, sp. 



Def. — The plates surrounding the body accord in number 

 and arrangement with the generic type. Main rays five, each 

 composed of a single joint. These are succeeded by others 

 until the last series amount to forty. Each subdivision, like 

 the main rays, is composed of a single joint. Column un- 

 known. 



This is an exceedingly minute species, from which circum- 

 stance we had given it the specific name minimus in our pro- 



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