EXPLANATION OF PLATE 52. 
85 
of which a few individuals only have hitherto been 
found, affords examples of many very delicate and 
beautiful mechanical contrivances, which throw im- 
portant light on corresponding parts of the fossil 
species of this, and of kindred genera that abound 
in strata of the Secondary series, and more espe- 
cially in the Lias, (See V. I. pp. 432. 433. 436.) 
Fig. 2. Pentacrinus Europaeus, discovered in the Cove of 
Cork, and on other parts of the coasts of Ireland, by 
J. V. Thompson, esq. (See V. I. p. 432.) In this 
figure several Individuals in different stages of de- 
velopment, adhere by the base of an articulated 
column to the stem of a Coralline. 
Fig. 2'. One of the Individuals magnified and fully ex- 
panded. See V. I. p. 433. 
Mr. J. V. Thomson has more recently conjectured 
that the Pentacrinus Europaeus, which in early life 
is fixed by its stem to other bodies, is produced 
from the ovum of the Comatula, and becomes after- 
wards detached, and forms a perfect Comatula, ca- 
pable of moving freely in the Ocean ; at one time 
crawling amongst sub-marine Plants, at others float- 
ing, or swimming like Medusae. (See Proceedings 
of Royal Society, London, June, 1835.) 
Fig. 3. Small Briarean Pentacrinite, adhering to a frag- 
ment of Jet from the Lias at Lyme Regis. (See V. 
I. p. 437, Note.) 
Fig. 4. Fragment of the column of Pentacrinites sub- 
angularis. The Vertebrae are nicely articulated to 
admit of flexure without risk of dislocation. The 
uppcmiost joint d. shews the lateral cavities for the 
articulation of auxiliary side arms. (Goldfuss. PI. 
Lll. f. g.) 
Fig. 5. Vertical Section of Fig. 4. In this Fig. and m 
