128 Cincinnati Society of Xaturat History. 



generations ; they then unite together to form the large 

 motile protoplasmic bodies named plas))wdia. The newly- 

 formed Plasmodium is distinguished by its greater size from 

 the swarm-cells, while it exhibits essentially the same move- 

 ments and changes of shape. The plasmodia gradually 

 increase in size, and as they grow assume commonly the form 

 of branched strands ; these spread over the surface of the 

 substratum, which is usually the decaying parts of plants, in 

 the form of veins and net-works of veins, giving rise to a 

 copiously-branched reticulated or frill-like expansion, which 

 covers surfaces varying in extent from a few to several centi- 

 meters. They are chiefly composed of a soft protoplasm of 

 the consistence of cream, which may be readily spread out 

 into a shapeless smear, and is usually colorless, but sometimes 

 exhibits brilliant colors of yellow, orange, rose, purple, etc. 

 The development of the plasmodium ceases with the forma- 

 tion of the spores within their sporangia. 



The formation of the sporangia out of the plasmodium 

 appears under three general forms, which, however, pass into 

 each other and are, therefore, not strictly limited. 



First : An entire plasmodium spread out on its substratum 

 becomes transformed into a sporangium, or it divides into a 

 variable number of unequal and irregular pieces, each of 

 which undergoes transformation. Such a sporangium lying 

 flat on the substratum, more or less elongated and flexuous, 

 often branched and reticulate, is termed a plasmcdiocarp. 



Second: Erect sporangia on a narrow or stalk-like base, 

 begin as node-like swellings on the branches of the plasmo- 

 dium, and gradually rise to their ultimate form as the sur- 

 rounding protoplasm flows into them and assumes an upward 

 direction. These sporangia are nearly always perfectly 

 regular in shape ; they may be globose, obovoid, somewhat 

 depressed, or more or less elongated, and are either stipitate 

 or sessile. 



Third: A number of plasmodia collect together from 

 every side and become fused into a single body, often of con- 

 siderable dimensions; from these combinations originate the 

 large spore receptacles which are called u-t/ia/ia. The com- 

 ponent sporangia may be regular in shape, standing close 

 together, in a single stratum, with entire connate walls: more 



