230 BOTANICAL GAZETTE [SEPTEMBER 
he announces that a sine qua non condition for obtaining a complete 
development of the fructification is the presence of a special 
bacterium, a Micrococcus related to M. latens. He demonstrated 
this by first isolating the coccus and then planting it alongside 
rods of Chondromyces on the surface of the same sterilized 
medium. It was only where the resultant colonies grew together 
and mingled that perfect fructifications of Chondromyces were 
- formed, although the relation does not appear to be lichenicolous 
in character. He affirms that if the Micrococcus be present, normal 
cultures can be obtained on many different kinds of media. I know 
of no further observations on this subject. ZEDERBAUER (11) 
cannot be quoted, because he was not working with Myxobac- 
teriaceae as he supposed. In my own cultures a filamentous fungus 
with septate hyphae was constantly present in small amount, and 
not infrequently the threads of this fungus are imbedded in the 
_cystophore, although never in the cysts. But ample observations 
make certain that whatever réle it plays, if any, it is not a necessary 
constituent of the fructification at any stage. 
The species of Chondromyces that have been so far described 
constitute a rather close evolutionary series; and the outstanding 
character in which the evolutionary forces are manifested is funda- 
mentally not one of form, size, or color, but of movement. Thus 
we may begin with a form like C. muscorum Thaxt., in which single, 
simple, unstalked cysts are formed. In C. serpens Thaxt. and 
C. lichenicolus Thaxt. there is a movement in a horizontal direction, 
resulting in sessile, elongated, and often confluent, coil-like cysts. 
The primary movement is vertical in C. gracilipes Thaxt. and a 
simple stalked cyst results. In some species there may be a 
forking of the stalk, but in most cases there is a radial movement 
from the primary stalked mass, resulting in the formation of heads 
of small cysts, for example, in C. crocatus. In these cysts there 
may be secondary migrations, a single one toward the center of the 
cyst in C. apiculatus Thaxt., or several, the centers of migration 
being separated at intervals in a radial line. The last is illustrated 
by C. catenulatus Thaxt., with its heads of cysts in chains. 
In the ontogeny of C. Thaxteri every stage in the vertical and 
radial line of evolution relative to this phenomenon of movement 
