PENTACRTNITES. 325 



degree of perfection than is retained in the existing Penta- 

 orinites ; and although the place, which, as Zoophytes, they 

 occupied in the animal kingdom, M'as low, yet they were 

 constructed with a perfect adaptation to that low estate, and 

 in this primeval perfection they afford another example at 

 variance with the doctrine of the progression of animal life 

 from simple rudiments through a series of gradually im- 

 proving and more perfect forms, to its fullest development 

 in existing species. Thus, a comparison of one of the early 

 forms of the Genus Pentacrinite, viz. the Briarean Pentacri- 

 nite of the Lias, (PI. 51 and PI. 52, Fig. 2. and PI. 53) with 

 the fossil species of more recent formations, and with the 

 existing Pentacrinus Caput Medusas from the Caribbean 

 Sea, PL 52, Fig. 1, shows in the organization of this very 

 ancient species an equal degree of perfection, and a more 

 elaborate combination of analogous organs, than occur in 

 any other fossil species of more recent date, or in its living 

 representative. 



Pentacrinites. 



The history of these fossil bodies, that abound in the lower 

 strata of the Oolite formation, and especially in the Lias, 

 has been much illustrated by the discovery of two living 

 forms of the same Genus, viz. the Pentacrinus Caput 

 Medusas,* (PI. 52, Fig. 1,) and Pentacrinus Europasus, PI. 

 52, Figs. 2, 2'. Of the first of these a few specimens only 

 have been brought up from the bottom of deep seas in the 

 West Indies ; having their lower extremities broken, as if 

 torn from a firm attachment to the bottom. The Penta- 

 crinus Europasusf (see PI. 52, Figs. 2. 2',) is found attached 



* See Miller's Crinoidea, p. 45. 



t See Memoir on Pentacrinus Europaeus by T, V. Thompson, Esq. Cork, 

 1827. He has subsequently ascertained that this animal is the young of the 

 Comatiila. 

 VOL. I.— 28 



