ENCRINITES. 129 



means of the base of the column being spread out, 

 something after the way in which such limy sea- 

 weeds as the Corallina officinalis attach themselves 

 to the sea-bed. 



Species of Crinoids belonging to the genus Bour- 

 getocrinus (allied to the living Rhizocrinus) occur 

 rather scantily in the Chalk, although I have found 

 them sometimes plentifully at Norwich, Guildford, and 

 near Lewes. Both Apiocrinites and Marsupites are 

 tolerably common in the Chalk at Margate, at the 

 base of the cliffs. In some places in the London 

 Clay, as at Witham, in Essex, joints of Encrinites 

 allied to the Pentacrinites y now common in West 

 Indian seas, are found. We have already seen the 

 relationship which the Crinoids bear to the star- 

 fishes, through such forms as Euryale and Comatula. 

 In like manner they are related to the sea-urchins 

 through such fossil forms as the Saccosoma of the 

 Oolite, and the Marsupites of the Chalk. 



