226 THE AMERICAN NATURALIST. [Vor. 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 fibrillz, | 
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, 
