CHAPTER V.—COMPARATIVE REVIEW.—MUCORINI. 149 
In the group of Piptocephalideae the archicarps are curved and so disposed 
that the pair has very nearly the form of an Q or of an inverted M. The surface 
of union lies in the apex of the bow (Figs. 73, 74 Z). In Syncephalis nodosa the 
archicarps are coiled spirally round one another. Up to the time when the con- 
jugation of the slender gametes is completed the development is essentially the 
same as in the first-mentioned cases, but then the product of conjugation swells at 
the place of coalescence into a spherical vesicle, which bulges on the convex side of 
the bow of the N. Protoplasm passes into it in proportion as it increases in size. 
When it has reached the limit of its growth, it is delimited by a partition-wall from 
each limb of the bow and becomes a nearly spherical zygospore ; it may at least 
be so called for the sake of clearness and simplicity, though it is plain that it is not 
the strict morphological equivalent of the zygospore of the first case, but is a 
daughter-cell of the zygospore, if the zygospore is the cell which results directly from 
the conjugation of the pair of gametes. If we adopt the proposed terminology, the 
spherical zygospore of Syncephalis 
is placed at the apex of the bow 
formed by the pair of suspensors, 
and each suspensor is divided by a 
transverse wall. 
The behaviour of the zygospores, 
while they are maturing, is essentially 
the same in both cases, apart of course 
from specific differences. The fatty 
matter in the protoplasm, which con- 
tinues to be dense and darkly granu- 
lar, usually collects into several large 
round drops. A further and exact ) 
insight into more delicate points of _Fıc.73. Piptocephatis Freseni jugation and formation of 
. 5 zygospores, the —. in the order of the numbers. Z a ripe 
structure in the protoplasm is scarcely ee a ee 
attainable owing to its opaqueness. 
The wall forms usually wart-like or conical projections on its free outer surface, in 
Piptocephalis even before the delimitation of the zygospore, only those parts re- 
maining smooth where it is in contact with the suspensors, and becomes differentiated 
into a stout episporium the colour of which varies from brown to black, and a thick 
stratified endosporium formed of more than one layer (Figs. 72 ¢, 71 C, 73 IE, 742). 
The latter has either its outer surface quite smooth, as in Chaetocladium, and the 
projections belong entirely to the episporium; or it is furnished with stout solid 
projections which fit into corresponding depressions in the episporium (species of 
Mucor, Sporodinia). Mortierella is the only exceptional case, in which the episporium 
is not rough on its outer surface and owing to its close adherence to the investing 
envelope is but little developed. 
In many species, and in the majority of those which have been named above and 
represented in Figs. 71-74, the ripe zygospore thus constituted lies naked and without 
any further covering between the suspensors, which ultimately wither and decay. 
But in some species an envelope is added to the parts already described in the 
zygospore. Short branches shoot out in a simple or multiple circlet in the more 



