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Il. SPECIES POTERIOCRINITES TENUIS. 
THIN VASE-LIKE LILY-SHAPED ANIMAL. 
Specific Character. 
A Crinoidal animal with a column formed of numerous round thin joints, 
surface of articulation radiatingly striated. The plate-like joints forming the 
cup-like body, articulating by minute strie. One arm proceeding from each 
scapula supporting two fingers. 
Locality. 
In the Mountain Limestone of the Mendip Hills, and in the Black Rock 
(the fourteenth bed of Dr. Bricur’s series; see Geol. Trans. Vou. iv. p. 193.) 
near the river Avon, Bristol, belonging to the same formation. 
Description. 
It is a much neater and smaller species than the former. 
Its CoLumn (fig. 1.) must have possessed near the summit a considerable | 
degree of muscularity, since the thin joints of this part appear to have yielded 
to the impression of the lower part of the pelvis joints, and the pressure of the 
muscle acting on them, so as to assume a slightly-waved marginal outline. 
The Pexvis (fig. 2. to 5.) together with the five intercostals (fig. 6. and 7.) 
and the scapulz (fig. 8. and 9.) adhere by slightly striated surfaces, and with 
the intervening pentagonal and hexagonal plates form a small and elegant trun- 
cated cup. 
The Arms (fig. 12. to 21.)—From the scapula proceeds immediately the 
cuneiform joint of the arm, it is very slender and long, yet in general construc- 
