2 26 THE AMERICAN NATURALIST. [Vol. XXXIX. 



It seems probable that there are really two forms of proto- 

 plasmic connections between cells in plants : first, those so 

 intimate that the plasma membranes are pierced and become 

 continuous openings inclosing a strand of granular cytoplasm 

 within ; and second, those in which the plasma membranes are 

 merely applied to one another without open communication. 

 The second form comprises the most delicate connecting fibrillas, 

 structures so fine that their minute structure is not understood 

 and we do not know how intimate may be the application of the 

 fibrillae to one another or to the surface of the cells. These are 

 the typical plasmodesmen of Strasburger which he considers as 

 organs of the plasma membrane, kinoplasmic in character, and 

 compares to cilia. The broad connections of the first group 

 have exactly the structure that would be expected of fused 

 pseudopodia, as Meyer pointed out. Whether the two types 

 insensibly grade into one another or whether each is a develop- 

 ment by itself is a problem of considerable interest, for if the 

 former possibility prove true, Strasburger' s conception and clas- 

 sification of plasmodesmen as organs of the cell will hardly 

 seem justified. 



When protoplasmic connections become so broad that cyto- 

 plasm flows or surges from one cell to another, an actual transfer 

 of nuclei sometimes takes place. Such conditions may illustrate 

 simply one extreme of the series of protoplasmic connections 

 that we have just discussed, but many of them introduce some 

 complexities, mainly through a certain resemblance to sexual 

 processes, so that they should be treated apart from general 

 protoplasmic connections. Some of them will be described later 

 under the head of " Asexual Cell Unions and Nuclear Fusions." 



Closely associated with protoplasmic connections is the inter- 

 esting subject of intercellular protoplasm which is receiving 

 some attention at present. The last papers are by Kny (:04) 

 and Michniewicz (: 04) who are studying conditions in the seed, 

 especially of Lupinus. By various reactions and physiological 

 studies, Kny has established an apparent identity of nature 

 between an intercellular substance, sometimes with starch 

 inclusions, and the cytoplasm of the neighboring cells. He 

 considers this substance to be intercellular protoplasm, that is, 



