160 BOTANICAL GAZETTE [uae | 
in cells of very diverse nature and in the period of complete 
rest. Their appearance in animals seems general and ind — 
phases of the life of the cell. : 
It may prove, however, not to be the same with plants. The : 
observations of Farmer, of Strasburger and his pupils, tend 
show that among plants these elements occur only in the tha 
lophytes and lower bryophytes ; and that they may not exist @ : 
all in vascular cryptogams and phanerogams. Such a difference 
between thallophytes and cormophytes on the one hand, atl : 
between the latter and animals on the other, is somewhat sit | 
prising when one considers the analogies presented in the fur : 
damental structure of the cell, especially in the phenomenad 4 
nuclear division, in the great majority of plants and animals : 
However, the question may depend wholly upon the difference 
between purely theoretical views. i 
Among lower plants in which centrosomes have beet : 
described by the preceding observers, they present morpholog 
cal variations analogous to those with which we are familiar ® 
animals. For example, in Fucus, in the developing oogonia até : 
the segmenting eggs, Strasburger has observed centrosomes 
rounded by well differentiated radial striations. Swingle 7 j 
made similar observations in the vegetative cells of Sphacelat : 
with this difference, that instead of having the form of a routs 
granule, the centrosome resembles a little box (boitonnet) 
dumb-bell, or is club-shaped. This centrosome divides, pes" 
during the resting period, and varies but slightly in size. 
these plants the centrosome seems to be without any 
