Chap. XVII.] STRUCTURE OP THE BLADDER. 



321 



branch (about twice enlarged), with the pinnatifid leaves 

 bearing bladders, is represented in the following sketch (Fig. 

 17). The leaves continually bifurcate, so that a full-grown 

 one terminates in from twenty to thirty points. Each point 

 is tipped by a short, straight bristle; and slight notches on 

 the sides of the leaves bear similar bristles. On both surfaces 

 there are many small papilla), crowned with two hemi- 



Fio. 17. 



( Vtrictdaria negleda. ) 



Branch with the divided leaves bearing bladders ; about twice enlarged. 



spherical cells in close contact. The plants float near the 

 surface of the water, and are quite destitute of roots, even 

 during the earliest period of growth.* They commonly in- 

 habit, as more than one observer has remarked to me, re- 

 markably foul ditches. 



* I Infer that this Is the ease 

 from a drnwin;; of n st^edlinc 

 given by Dr. Wnrmlug In his 

 paper, " Rldrne til Kundsknlton 

 om Lentlbularlaeete," from the 



' Vldenskabellge Meddelelser.' 



Copenhagen. 1874. Nos. a-7, pp. 

 3.-i-58. fCf. KamlenskI, ' But. 

 Zelt.' 1877, p. 765.] 



