UPPER, OR FLINTY CHALK. 183 



tion very small. From the diminutive size, and elongated form of this 

 specimen, it may probably be a portion of the side-arms, or lateral ap- 

 pendages. 



Fig. 1 2, is composed of eight ossiculae ; and is evidently part of the 

 vertebral column of the present species. 



27. Part of the vertebral column of a pentacrinite. 



This specimen is formed of eleven thin pentagonal vertebrae, with 

 markings on their articulating surfaces, precisely similar to those re- 

 presented in Tab. xiii. fig. 64, Org. Rem. Vol, ii. 



28. A single vertebra, of a quadrangular form, the angles rounded, the 

 surface ornamented with figures resembhng a floret of four rays. 



The entrochite. No. 1 170, of Lhwyd, is composed of ossicular, perfectly 

 resembhng the specimen here described. Trochitae of four rays are 

 very rare ; Mr. Parkinson mentions that he had seen but one (fig. 59, 

 Tab. xiii. Vol. ii. Org. Rem.) and that is very dissimilar to the fossil in 

 question. 



MARSUPITES. 



This genus is formed for the reception of a fossil that has hitherto 

 been placed among the encrinites, from which however, it differs most 

 essentially, in being destitute of a vertebral column, and processes of 

 attachment ; hence it is obvious, that the recent animal, instead of being 

 fixed to one spot, was capable of locomotion, and floated ad libitum, hke 

 the Medusae and some other zoophytes. 



Mr. Parkinson, whose publication on the Organic Remains of a former 

 World, forms an important era in oryctological science, was the first 

 author that accurately noticed these interesting remains. In his 2d vol. an 

 admirable description is given of the pelvis of the animal, under the name 

 of tortoise encrinite ; and very recently, the structure of the original 

 has been ably illustrated by the ingenious author of The Natural History 

 of the Crinoidea, who has adopted the name by which I have been ac- 

 customed to distinguish it. 



The following definition is the result of an attentive examination 



