232 



HISTORICAL PALAEONTOLOGY. 



" stalked " Crinoids, the Jurassic rocks have yielded the re- 

 mains of the higher group of the " free ;; Crinoids, such as 



Fig. 162. Pentacrinns fascicu'.osns, Lias. The left-hand figure shows a few of the 

 joints of the column ; the middle figure shows the arms, and the summit of the column 

 with its side-arms ; and the right-hand figure shows the articulating surface of one of the 

 column-joints. 



Saccosoma. These forms resemble the existing "Feather- 

 stars" (Comatitla) in being attached when young to some 



