222 . THE AMERICAN NATURALIST. | [Vor. XXXIX. 
splíere is connected with its neighbors generally by six strands 
of protoplasm, only a few of which could possibly be left by the 
successive cell divisions. The majority must have developed as 
outgrowths from the plasma membrane of the cell. 
Numerous instances of cytoplasmic connections among the 
fungi have been reported by many authors. A general review 
of the subject is presented by Kienitz-Gerloff (:02) and in a 
lengthy paper of Meyer (:02). The protoplasmic connections 
fall into two groups: (1) those that remain in the center of the 
wall after a cell division, and (2) the lateral unions and clamp 
connections which are developed entirely independently of cell 
division. Connections of the first type, 7. e., those between 
daughter cells, appear to be very general in the Ascomycetes 
and Basidiomycetes and are essentially similar to the strands 
between cells of the Rhodophycea. They are especially well 
illustrated in members of the Laboulbeniacee (Thaxter, '96; 
see Fig. 16,f). In the second group are the clamp connections 
(Fig. 16, g), characteristic structures of the tissues of fleshy 
forms of the Basidiomycetes, and the lateral unions between 
cells of closely entangled hyphæ which are well known in a 
number of forms and have been followed in cultures from germi- 
nating spores. It is probable that the fusions between sporidia 
in the smuts are also of this class, although De Bary and others 
have attached sexual significance to the phenomenon (especially 
as illustrated by Tilletia). Harper (99a) has studied the fusions 
of the conidia of Ustilago and finds that they concern the cyto- 
plasm alone. However, Federley (:03-:04) has reported a 
nuclear fusion in one species (Ustilago tragopogonis pratensis 
Pers. but states that others agree with Harper's account. 
Extensive experiments of Brefeld have shown that the fusions 
of sporidia depend largely upon the character of the nutrient 
media and are less likely to occur when the conditions are favor- 
able. He considers the fusions as purely vegetative processes 
comparable to the unions of germ tubes of spores (e. g., Nec- 
tria, Sclerotinia, Rhyparomyces, etc.) into a common mycelium 
and to the connections between hyphz of Basidiomycetes. 
Recent studies of Blackman (:04.a) indicate: also that sexual 
processes should not be expected at this period in the life his- 
