12 Proceedings. 



pores intermixed with the epidermal cells ; in most 

 flowering plants the distribution of the air-pores to the 

 epidermal cells is that the latter are greatly in excess of 

 the former, as 10 to I, 50 to 1, 200 to 1, and so on, but in 

 this species of Iris almost every epidermal cell touches an 

 air-pore, except in those portions which cover the 

 ribs of the leaf. Further, each epidermal cell possesses a 

 peculiar round body, as though it were a protuberance, or 

 papilla, on the external cell wall. By means of a paper 

 model of the flower, the mechanism by means of which 

 cross-fertilization was effected by insects, was illustrated. 



