24 | Botanizing on the Colorado Desert. [ January, 
instead of passing between peripheries as in the instance of non- 
union, unite the segmental ganglia by making another ganglion — 
its motor projection. ‘ 
Carpenter (“ Principles of Comparative Physiology,” p. 642) 
expresses this view: ‘“ When different organs are so far special- 
ized as to be confined to distinct portions of the system, and each 
part consequently becomes possessed of a different structure and — 
is appropriated to a separate function, this repetition of parts in — 
the nervous system no longer exists; its individual portions — 
assume special and distinct offices, and they are brought into 
much closer relationship to one another by means of commis- — 
sures or connecting fibers, which form a large part of the nervous 
system of the higher animals. It is evident that between the most : 
simple and the most complex forms of this system there must be ~ 
a number of intermediate gradations, each of them having a rela- 
tion with the general form of the body, its structure and economy 
and the specialization of its distinct functions. This will be found 
on careful examination, to be the case; and yet, with the diversity : 
of its parts as great as exists in the conformation of other organs 
its essential character will be found to be the same throughout.” 
Segmental union, thus, is accomplished through efferent nerves — 
no longer penetrating to primary organs, but passing to nerve — 
centers of other segments, for the purpose of producing coordi 
nated movements, and consequently to exert an inhibitory effect © 
thereupon. 
[Zo be continued, | 
“7° 
oe 
BOTANIZING ON THE COLORADO DESERT. 
BY EDWARD LEE GREENE. 
li. 
ETWEEN Coyote Wells and the next station lie some, twen 
two miles of almost uninterrupted plain. The white cl 
the grease bushes, contrary to the rule of desert growths, are 
leafy, their abundant foliage is of precisely the same dull whitish — 
color as the clay in which they grow. Over this smooth an¢ 
slightly yielding clay the walking was very easy, and I mad 
