CRINOIDEJE. 



throughout life, others naked through a part of their 

 existence, and others which are enclosed in a tube 

 throughout their lives. In like manner may we expect 

 to find in the order of Crinoidese animals fixed through- 

 out life, others fixed through a portion of their existence 

 only, and others which are free almost from their births. 

 As yet, however, we know so little of the history of the 

 tropical species that we cannot pronounce with certainty, 

 and at present we can only recognise two families of 

 Crinoids as properly constituted, such as are stalked as 

 the Encrinites and the Comatula, and such as are sessile, 

 as the genus Holopus of M. D'Orbigny. This division can 

 only be regarded as provisional. 



