1895. ] New or Peculiar Zygomycetes. 515 
sporiferous heads, moreover, though similarly formed at the 
tips of ultimate curved branchlets, are clearly distinguished 
from the fact that the sterigmata are invariably two celled, 
the upper budding from the lower and not a result of septa- 
tion, each cell bearing terminally several spore chains, or 
sporangia, if we adopt the terminology of Van Tieghem, each 
spore chain consisting of but two spores instead of six. 
The characters of the non-sexual form of reproduction are 
of secondary importance, however, as compared with those 
of the sexual, which was not observed in connection with 
D. cornuta, but appears to be common in the American species 
and are quite without parallel among the Mucorinee. Th 
vegetative mycelium is composed of rather irregular branch- 
ing hyphz, for the most part aseptate and much smaller in 
diameter than the fertile ones. From these vegetative hyphz 
are produced lateral branches which, becoming slightly swol- 
len terminally, attach themselves usually to the fertile hyphe 
of mucors. This lateral branch fixes itself firmly to the host 
filament by a sucker-like tip which eventually penetrates the 
host by means of an irregular protrusion, usually not conspic- 
uously developed though sometimes extending a short dis- 
tance beyond its point of entrance along the inner surface of 
the wall of its host. These suckers are the only parasitic 
organs which were observed in :he material examined, and 
it is uncertain whether they are characteristic of the ordinary 
hyphe or invariably represent the first stages in the produc- 
tion of zygospores, since they were always found associated 
with the latter. 
The successive stages in the formation of the zygospores 
are illlustrated by figs. 10-13. The lateral branch already 
mentioned after it has fastened upon the host, becomes 
divided into two parts by a septum, usually nearer the fila- 
ment from which it arises, and these two parts proceed to 
Conjugate with one another, the outer becoming eventually 
Separated from the parent filament and receiving from the 
inner the material. derived from its parasitic union with the 
Mucor. The outer gamete soon becomes nearly spheri- 
cal, enlarging greatly to form the zygospore itself, while the 
inner, which gradually assumes the appearance of a mere 
outgrowth from the mucor, sends out simple or once-branched 
finger-like processes which grow about half way round the 
Mature spore and are at first more or less yellowish from the 
