INTRODUCTION. 
XXV 
Threads bearing zoogonidia. Asexual reproduction by zoogonidia ; 
sexual by antheridin and oogouia, producing oospores 
Suprolegniacece. 
Threads bearing gonidia. Asexual reproduction by gonidia, and 
thick-walled resting spores; sexual by zygospores 
Entomophthoracere . 
B. Threads obsolete. 
Sporangia alone, without mycelium. Asexual reproduction by 
zoogonidia; sexual by zygospores Chytridiacece. 
Filiform byphse soon disappearing. Spoiangia thick-walled 
Protomycetacece. 
Some of these sections are unrepresented in this volume, 
such as the Saprolegniacece, growing on fish, insects, or aquatic 
plants, for the most part, and the Entomophthoracece, which are 
usually parasitic on living insects. The Mucoracem has some 
six representatives, the Peronosporacecv. about three, the lower 
sections Chytridiacem two species, and the Protomycetacece a 
single species. With so small a number no detailed analysis of 
the genera is necessary. We may be excused for directing the 
attention of cultivators of garden plants, or field produce, to the 
devastation caused by the various species associated together in 
the genera which make up the section Peronosporacece . 
Two small groups, of uncertain affinity, but containing species 
of the utmost importance, are the Saccharornycetes, or yeast 
fungi, and the Schizomycetes, or microbes, which infest the 
tissues of auimals and plants. The individuals composing 
these groups are often infinitely minute, of low and simple 
organization, but powerful by their numbers, and the future 
may have much to reveal to us of their relations to health and 
disease. 
The final order to bo alluded to here is the problematic 
Myxomyeetes , sometimes called Myxogastres, or, by some authors, 
Mycetozoa. The individuals are for the most part small, from 
the size of a pin’s head to that of a rape seed, but occasionally, 
by confluence, much larger. They inhabit moist situations, 
growing upon dead leaves, rotten wood, or similar substances, 
and, in their eai’ly state, are soft and gelatinous. This is the 
vegetative stage, in which it has been assumed that they are 
offsets from the animal world. The final, or reproductive stage 
is admitted to be analogous to, if not in affinity with Fungi, 
Producing distinct spores in a powdery mass. These spores 
on germination “give origin to one, two, or more naked cells, 
which possess the power of movement, due to the protrusion of 
Pseudopodia, or the presence of a cilium ; these cells are known 
as swarm-cells. The swarm cells possess a nucleus, multiply 
by bipartition, and eventually coalesce to form a plasmodium 
ln the following manner. After the production of numerous 
xwarm spores by repeated bipartition, little groups are formed 
by the close approach of two or more of these bodies ; these 
groups often disperse again, but eventually the components of 
a group coalesce, and lose their individuality ; this coalescence 
