42 platycrind^e. platycrinus. 



Synonymes and References. 



Platycrinites tuberculatus. — Miller's Cr'moidea, p. 81. 



Phill. Geol. York. PL III. fig. 17, p. 204. 



Formation and Localities. 



Carboniferous Limestone. — Bolland, and the Mendips. 



The dorso-central plate has generally a very prominent tubercle at each of its angles, 

 but in some instances a greater number than five occur on the plate. Tubercles also 

 occur on the perisomic plates, chiefly near their lower edges, but this arrangement is not 

 constant. The abdominal plates are mostly conical in their centres. The mouth is 

 placed laterally and exactly on a line with the excavations for the rays. It was evidently 

 not proboscidial. The structure of the column and the number of rays are unknown. 

 The base of attachment is also unascertained. 



Doubts have been entertained as to whether the tuberculatus and the rugosus are not 

 identical ; but this opinion is not founded on satisfactory evidence. 



12. Species. Platycrinus laciniatus. (Gilb.) 

 PI. V. fig. 1, rt, h, c. 



Definition. — Dorso-central plate more conical than in the typical species ; perisomic 

 plates with small excavations for the rays ; all the plates are tuberculated, with 

 calcareous strings crossing the sutures. Rays and column unknown. 



Synonymes and References. 



Platycrinus laciniatus. — Phill. Geo. of York. PL III. fig. 18. 



Aust. Ann. ^ Mag. Nat. Hist. vol. 10, p. 109. 



