34 



PLATYCRINIDiE. I'LATYCRINUS. 



Synonymes and References. 



Platycrinites granulatus. — Mill. Nat. His. Crinoidea, p. 82. 



Phillips. Gcol.of Yorlcshire, PL HI. fig. 16. 



Messrs. Austin, Ann.!<^Mag.Nat.His.\o\.\0,'^o.m, p.l09. 



Witry. Auc mem., de VAc. de Bmx. III. PL 3,/. 5, et. 6. 



Muenst. Deilr. zur. Pctr. I. p. 5. 



Koninck. t. F. fig. 2, a, b, p. 4.3. 



M. Edvv. ap. Lamarclc II. p. 666. 

 Encrinites granulatus.— Schloth. NacJitr. z. Petref. III. p. 94. PL 26,/. .3, a, h, c. 

 Platycrinites granulosus. — Blain. Man. d'Acl. p. 292. 



Formation and Localities. 



Carboniferous or mountain limestone. — Bolland; Mendip Hills; Leigh Downs, and the 

 Black Rock, near Bristol; Hook point, Wexford; Granagh Ferry, Kilkenny; and Tournay. 



Notwithstanding the various localities in which the Granulatus has occasionlly been 

 found, the species was of rare occurrence, if the absence of its remains in a fossil state 

 may be considered as a proof of its scarcity. 



Description of the Calcareous Frame Work. 



The Dorso-central Plate.- — In this species the dorso-central plate is ornamented 

 with highly raised granulte, which give it a very elegant appearance. Five rows of 

 granulse range with great regularity from the columnar point of attachment, to each of 

 the five angles of the plate; each pair of rows forming two sides of an acute triangle, 

 the edges of the plate completing the figures. Other well defined lines of smaller granuUe 

 run in the same direction and stud the intermediate spaces. 



The Perisomic Plates— Are five, broad, and slightly spreading towards their upper 

 edges; the excavations for the insertion of the rays are slight, several lines of granulte 

 radiate from the base of each ray, on the superior edges of the perisomic plates, and 

 gradually expand until they terminate at the lower and outward angles of the plates, where 

 they meet the lines of granulae on the dorso-cental plate. The intervening spaces are 

 ornamented with rows of smaller granular as before observed in the dorso-central plate 



