834 UTRICULARIA NEGLECTA. [Chap. XVII. 



drawing. These bristles, together with those borne by the 

 antennse, form a sort of hollow cone surrounding the en- 

 trance. 



The valve slopes into the cavity of the bladder, or upwards 

 in Fig. 18. It is attached on all sides to the bladder, 

 excepting by its posterior margin, or the lower one in Fig. 

 19, which is free, and forms one side of the slit-like orifice 

 leading into the bladder. This margin is sharp, thin, and 

 smooth, and rests on the edge of a rim or collar, which dips 

 deeply into the bladder, as shown in the longitudinal section 

 (Fig. 20) of the collar and valve; it is also shown at c, in 

 Fig 18. The edge of the valve can thus open only inwards. 



Fio. 20. 

 ( Utrieularia negleda.) 

 LongitDdinal vertical section througli the ventral portion of a bladder; 

 showing valve and collar, v, valve ; the whole pnyection above e 

 fonuB the collar ; 6, bifid processes ; s, ventral surface of bladder. 



As both the valve and collar dip into the bladder, a hollow 

 or depression is here formed, at the base of which lies the 

 slit-like orifice. 



The valve is colourless, highly transparent, flexible and 

 elastic. It is convex in a transverse direction, but has been 

 drawn (Fig. 19) in a flattened state, by which its apparent 

 breadth is increased. It is formed, according to Cohn, of two 

 layers of small cells, which are continuous with the two 

 layers of larger cells forming the walls of the bladder, of 

 which it is evidently a prolongation. Two pairs of trans- 

 parent pointed bristles, about as long as the valve itself, 

 arise from near the free posterior margin (Fig. 19), and point 

 obliquely outwards in the direction of the antennaj. There 



