156 THE MECHANICAL FUNCTIONS. 



dea, or lily-shaped tribe, (of which, Fig. 94, representing 

 the Pentacrirms europxuSj is an example;) for they consist 

 chiefly in the addition of a jointed stalk, which is made to 

 proceed downwards from the centre of the whole assem- 

 blage of rays, and which is to serve as a common stem for 

 sustaining the whole mass; while the branches themselves 

 are carried up, and folded inwards. The lower joint of the 

 foot-stalk is a little expanded, in order to procure a more 

 extensive base of support; and the whole structure thus pre- 

 sents a remarkable resemblance to a liliaceous plant. 



