122 ANNULOIDA. 



seem to be the most probable one ; but, as before remarked, 

 good authorities regard the excentric " proboscis " as the 

 mouth. 



In another group of Crinoids, represented by the living 

 Feather-stars (Comatula) and the extinct Saccosoma (fig. 77), 



Fig. 77. Saccosoma pectinata, a free Crinoid. Jurassic. 



the animal is only stalked when young, and in its adult con- 

 dition leads a free life. The young form in the members of 

 this group is supported upon a jointed calcareous column, by 

 which it is fixed to some foreign object ; and at this stage it in 

 no respect differs from the ordinary stalked Crinoids. At a 



