EXPLANATION OF PLATE 52. 86 



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. Thompson 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 Medusfe. (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 

 uppermost joint d. shews the lateral cavities for the 

 articulation of auxiliary side arms. (Goldfuss. PI. 

 LII. f. g.) 



Fig. 5. Vertical Section of Fig. 4. In this Fig. and in 



