PoTEiiiociiiNiTEs. RADIATA. CRINOID^. 495 



5. P. Briaereus. — Auxiliary side-arms angular, in a single series ; column 

 smooth. MUl. Crin. 56 — In Lias. 



Gen. POTERIOCRINITES.— Pelvis of five joints, with five 

 costals ; fingers of a single series of joints ; column not en- 

 larging, round ; central canal round ; articulating surface 

 of the joints radiated ; auxiliary side-arms round. 



1. P. crassus. — Joints of the fingers thick ; plates of the pelvis articulating 

 by transverse ridge-like processes. — Mill. Crin. 68. — Carboniferous Limestone. 



2. P. tenuis — Joints of the fingers slender ; plates articulating by minute 

 strife. Mill. Crin. 71. — Carboniferous Limestone. 



Gen. CYATHOCRINITES.— Pelvis of five plates, with five 

 costals ; the fingers of a single series of joints; column not 

 enlarged ; articulating surface of the columnar joints radia- 

 ted ; auxiliary side-arras round, and placed irregularly, 



1. C. planus — Column and central canal round ; plates smooth.— Mi//. Crin. 

 85. — In Carboniferous Limestone. 



2. C. tuberculatus. — Column and central canal round ; costal plates tuber- 

 culated. — Mill. Crin. QQ,— Carboniferous Limestone. 



3. C. rugosus — Column round ; central canal petal-shaped ; costal plates 

 with angular rugged strise — Mill. Crin. 89 Carboniferous Limestone. 



4. C. quinquangularis — Column and central canal pentangular ; costal plates 

 smooth. — Mill. Crin. 92. — Carboniferous Limestone. 



Gen. ACTINOCRINITES.— Pelvis formed of three plates, 

 with five costals and one intercostal ; fingers of two series of 

 joints ; column and canal round, the articulating surfaces 

 radiated ; auxiliary side-arms round and irregular. 



1. A. triacontadactylus. — Thirty fingers proceeding from five scapulae.— ilfe//. 

 Crin. 95. — Carboniferous Limestone. 



2. Polydactylu^. — More than thirty fingers proceeding from five scapulae.-^ 

 MUl. Crin. \Q^.— Carboniferous Limestone. 



Gen. RHODOCRINITES.— Pelvis of three plates, with five 



costals and five intercostals ; fingers of two series of joints ; 



column not enlarging, round, the canal' petal-shaped. 



1. R. TjerMs.— Auxiliary side-arraa round and irregular*— ilfj'//. Crin. 106.— 

 Carboniferous Limestone. 



