268 



" Encrinus, capite stellato ramoso dichotomo, stipite pentagono, 



equisetiformi. 



" The stem and head of this animal, in its present state, measures 

 about fourteen inches, the stem is about thirteen inches in height, and 

 about the third of an inch in diameter,, lessening a little towards the 

 top : it is formed of pentagonous joints, or vertebrae, placed regularly 

 over one another, which are of a testaceous substance, and united by 

 very thin cartilages, as appears by examining minutely the base of 

 the lowest vertebra, where it is fastened to the starry indentures of 

 the joint: this makes the vertebrae capable of bending at the will of 

 the animal, in any direction *. 



" If we examine the five furrows or channels along the stem, we shall 

 discover a small hole between every vertebra ; and in the centre of the 

 base of the lowest, we shall find a small hole there, which probably 

 communicates through the middle of all the vertebrae, to the cavity 

 in the centre of the head. 



" Along this stern, at different distances, from an inch and a quarter 

 to a quarter of an inch in length, we observe many series of five cy- 

 lindrical jointed arms, each series is of equal length, and placed in a 

 wheel or whirl-shaped form, like the equisetum or horse-tail plants. 

 Each arm is inserted in one of the five cavities of a vertebra, and each 

 joint into one another, that the upper end of one joint inclines over 

 the lower end of the next to it, which it appears, at the same time, 

 to inclose with a small margin. These joints are generally about one- 

 twelfth of an inch in length, and the same in diameter, and have a 



* There can be little reason to doubt, that the membranous substance, mentioned Page 

 1 66, as separated from the surface of a trochites, by the action of the muriatic acid, was 

 originally of a similar nature, with the cartilage which is here described as interposed be- 

 tween the vertebrae of the pentacrinite. 



