39° BOTANICAL GAZETTE [May 
contains several nuclei, and after surrounding itself with a wall becomes a 
spore. According to the author the process of spore formation in the Ceph- 
alidee corresponds in all respects to that in forms characterized by sporangia 
of the ordinary type, and the homology between the spore rowsof this section 
of the mucors and typical sporangia, which was first maintained by Van 
Tieghem in his well known memoirs, is thus considered to be fully substan- 
tiated. 
The most important portion of the paper is that which deals with the 
nuclear history of the process of conjugation, which was studied in a limited 
number of the species mentioned, and the subsequent history of the zygospore 
up to the time of its germination. The young zygospore is said to contain 
sometimes thousands of nuclei derived from each gamete, and as the spore 
matures these nuclei gradually disappear. As soon as the last have disap- 
m 
spore. These bodies, to which the author gives the name “ embryogenic 
bodies,’”’ appear to be derived from the nuclei which have disappeared ; though 
they are not formed nuclei, consisting of naked masses of protoplasm, 
doubtless nuclear in its nature. The embryogenic bodies later fuse in each 
group. The two resultant masses, which thus replace the groups, are called 
embryogenic spheres, and having surrounded themselves with two distinct 
walls constitute the “spheres embryonaires”’ of the mature zygospore. When 
the spore is about to germinate these spheres lose their walls, unite to form a 
single central mass in which numerous nuclei then make their appearance, 
which, after a single mitotic division, pass out into the hypha of germination. 
In the formation of the azygospores the history is exactly the same except 
that there is but one group of embryogenic bodies, and consequently but one 
embryonic sphere in the mature spore. The author considers the union of the 
embryogenic bodies as representing a sexual union, and for this reason holds 
that the azygospores are as truly sexual spores as the zygospores them- 
selves. The phenomenon of conjugation is thus held to be a prone : 
secondary importance and not sexually significant in the group. To 
who is not inclined to attribute sexual significance to all nuclear pe 
the question naturally occurs in this connection whether the fina] union of 
the embryonic eae may not represent a sexual union rather than that of 
emb the nuclear material of which may perhaps have 
been decived | in either group from the same gamete; the delay in the fusion 
of the former finding a parallel in the nuclear history of the zygospore of 
Basidiobolus. 
It may be mentioned that of the forms investigated in the paper two 
species of the genus Mucor are described as new; one J/. rigidus being 
closely allied to A. mucedo, while the other, J. rubescens, iS remarkable for 
en a ja 
