POTERIOCRINID^. — POTERIOCRINUS. 79 



Synontmes and References. 



Poteriocrinus plicatus. — Messrs. Austin. An. Sf Mag. Nat. Hist. Vol. 10, page 108, 

 ^ Vol. 11. page 196. 

 crassus. — L. de Kon. Anim.Foss'. Belg. PLF.fig 4. a Sf b. 



Formation and Localities. 



Mountain limestone. — Mendip hills ; Black Rock, Avon Banks, Bristol ; altered 

 beds of mountain limestone, Clevedon Bay. 



This species appears to be but sparingly diffused through the mountain limestone, 

 having been met with in only a few localities, and even there in very limited numbers 



The crenulated lip like expansions on the articulating edges of the plates as represented 

 in our ninth plate, fig. 4 e, are interesting points of structure. 



The figures which M. L. de Koninck has given in his valuable work on the Belgic 

 carboniferous fossils, of the external and internal form of a ray bearing plate, but which, 

 probably misled by Miller's restored figure, he has erroneously referred to the Poterio- 

 crinus crassus, bears close resemblance in its wavy folds to the form of the ray bearing 

 plates of this species. 



6. Species. Poteriocrinus radiatus. (Austin.) 

 PL 10. fg. la,lb. 



Definition. — Body conical, the plates ornamented with several bands of well defined 

 ridges which traverse the plates and cross the sutures. These elevate! radiations unite 

 with each other and form several series of triangles around the body. ]\Iouth centrical 

 and proboscidiform ; rays bifurcated; column slender. 



Synonymes and References. 



Poteriocrinus radiatus. — Messrs. Austin, .4nn. S; Mag. Nat. Hist. Vol. 10, 11, pages 

 108 and 196. 



