DESCRIPTION OF THE FOSSILS. 
205 
POTEIIIOCKTNUS. — The pelvis of this genus was unknown to Miller. 
It may be described as a tripartite ? supracolumnar joint, having its upper 
face marked with five ridges and hollows for the reception of the five 
costals (pelvis of Miller). See PI. IV. fig. 20. The upper columnar 
joints enlarge in diameter, but diminish in thickness, and a considerable 
number of them are anchylosed so as to form a conical base to the 
pelvis. The alimentary canal is pentagonal, not round as Miller states. 
A young specimen is figured to shew the arms in the rudimentary 
state. PI. IV. fig. 5, 6. The plates of the body are all clearly defined 
except the second costals (Miller) which are only partially divided across. 
P. impresus. Ph. PI. IV. fig. 1. Whitewell ; Bristol ; Arran. 
Conical : angles of tlie plates indented ; scapular articulation Emulate, excavate, 
| of the breadth of the plate. Pelvis thin. 
P. conicus. Ph. PI. IV. fig. 3, 7- Bolland. 
Conical, contour rather pentagonal ; scapular articulation the whole breadth of the 
plate, emarginato-pentagonal, level. 
P. granulosus. Ph. PI. IV. fig. 2, 4, 8, 9, 10. Bolland ; Belmore moun- 
tain, near Enniskillen ; near Kirkaldy. 
Hemispherical, delicately granulose, sutures grooved; scapulae very wide, their 
upper surface articulating by the whole breadth of the plate, ovato-lanceolate, emargi- 
nate within. 
P. ? nobilis. Ph. PI. III. fig- 40. Bolland. 
Mr. Miller named Mr. Gilbertson’s noble specimen of this cyathocr. tuberculatus, 
and under this name it has been beautifully figured by Mr. J. Sowerby. But it does 
not belong to that genus. The interscapular plates are remarkable. 
P. ? Eo-ertoni. Ph. PI. Ill- fig. 39. Florence Court ; Hawes. 
First costals (pelvis of Miller) pentagonal ; the whole series of plates from thence 
to the cuneiform base of the fingers similar ; fingers ten, short ; surface granulated. 
Column granulose, with moniliform joints and crenulated sutures: some specimens 
have equal, others unequal joints. This beautiful species is abundant at Florence 
Court, where it has been collected by Lord Cole and Sir P. Egerton. The anchy- 
losed upper joints of the column make it somewhat resemble the figure of eugeniacrinites 
(Miller), but it is really allied to poteriocrinus. 
The following species belong to new genera. 
Euryocrinus concavus. Ph. PI. IV. fig. 14, 15. Bolland. 
Pelvic opening pentagonal; arrangement of plates like encrinus, internal cavity 
very large. 
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