95 



seem also to be sufBcient to account for neither of these 

 bodies having been found fossil. From similar considerations 

 the remains of the tubuliferous polypi can hardly be ex- 

 pected to be discovered in a mineralized state. 



Encrini and Pentacrini. — Our attention is now claimed 

 by a series of animals rendered interesting, not only by 

 their curious forms and extraordinary structure, but also by 

 their being among the earliest inhabitants of this planet. 

 Hence they are so far aliens of this world, that whilst im- 

 mense tracts of rocks are literally formed of the entombed 

 remains of diflPerent species in a mineralized state, only five 

 or six fragments of the remains of one of these numerous 

 species have yet been discovered in a recent state. 



. The general characters which embrace the different 

 genera and species of these animals are, — an acephalous 

 animal, attached by a radiciform, subarticulated base, from 

 which arise cylindrical, oval, or pentagonal vertebrae pos- 

 sessing pentaphylloidal or stelliform articulating surfaces 

 and central openings, and forming an articulated tubular 

 spine, sujDporting a pelvis from which proceed articulated 

 arms, hands, fingers, and tentaculae, forming a body which 

 bears a floriform appearance. 



These animals appear to have had a considerable range 

 for the seizure of their prey, without possessing absolute 

 locomotion ; the peculiar mode of the articulation of their 

 vertibrse affording them a great degree of mobility, with 

 considerable security against dislocation. They have been 

 hitherto classed under two genera ; one, the encrinus, with 

 chiefly cylindrical vertebrae ; the other, the pentacrinus, with 

 principally pentagonal vertebrae. 



The encrinus has been divided into species, which have 

 been hitherto distinguished chiefly by, and named ac- 

 cording to, the characters of the base of the floriform 

 part of the animal, with which the uppermost vertebra is 

 articulated. 



