I04 Natural History Bulletin. 



rowed, and in some cases shows a disposition to unite or blend 

 with the stalks of neighboring sporangia. In many cases the 

 stipe is continued upwards, more or less definitely into the 

 cavity of the sporangium, and there forms the columella, some- 

 times simple and rounded like the analogous structure in 

 Mucor imicedo, sometimes as in Comatridia branching again 

 and again in wonderful richness and complexity. 



Each sporangium is at maturity filled with numerous uni- 

 cellular spores. These are usually spherical, sometimes flat- 

 tened at various points by mutual contact; they are of various 

 colors, more commonly yellow or violet brown, are sometimes 

 smooth (?) but generally roughened either by the presence 

 of minute warts, or spines, or by the occurrence of more or 

 less strongly elevated bands dividing reticulately the entire sur- 

 face. The spores are in all cases small (.003-.020 mm.) and 

 reveal their surface characters only under the most excellent 

 lenses. Associated with the spores in the sporangium occurs 

 the caplllitium. This consists of most delicate thread or hair- 

 like elements, offering the greatest variety both in form and 

 structure. The threads composing the capillitium are not to 

 be regarded, even when free, as cells, nor even of cellular 

 origin; they are on the other hand in such a case, simply 

 shreds and strands of the original plasmodium, portions that 

 have not been used in the formation of spores and are accord- 

 ingly modified in such wise as to be useful in spore dispersal. 

 The capillitium threads may be solid or hollow, the}^ niay 

 occur singly or be combined into a net, they may be terete or 

 flat, attached to the peridial wall or free, simple or adorned 

 with bands or spires and knobs in every variety, uniform or 

 profusely knotted and thickened at intervals, and burdened 

 with calcic crystals. In many cases, as remarked, the capilli- 

 tium contributes materiall}^ to the dispersal of the spores; in 

 others, it doubtless contributes mechanically to the support of 

 the peridial wall and renders so far persistent the delicate 

 sporangium. For more exact description the reader is again 

 referred to the specific delineations which follow. 



