Structure and Affinities of Leuconostoc mesenteroides. 79 
fact disposes of the suggestion that they might represent hetero- 
cysts such as are met with in the group of the Cyanophyceae. 
Whilst the structural characters of the cell-wall in spores and 
heterocysts and especially the pore and polar granule of the 
latter would be almost impossible to detect in such small cells 
as those of Leuconostoc, yet it must be remembered, that both 
the spores and heterocysts of Cyanophyceae have very definite 
staining reactions which distinguish them from vegetative cells. 
1 2 cm. 
Sess 
Fic. 2. G. Surface view of colony grown on Io % sucrose-agar. 
H and I. Surface view of colonies grown in sucrose solution. 
Cell-division generally takes place in one direction only so 
that the cells form short filaments which, however, seldom reach 
more than eight cells in length before breaking up, and generally 
there is a considerable amount of mucilage produced between 
the successive divisions so that the cells appear in groups of two. 
Occasionally (or fairly frequently in the form nuda) tablets 
consisting of four cells are seen. This deviation from the normal 
method of division cannot be regarded as pathological as it 
occurs in healthy, rapidly growing cultures. As this is the case 
