464 The Naturalist Brazilian Expedition, [May, 
The products in both cases are the tailed locomotive forms, which 
are, according to all observers, probably true single cells, which, 
from the earliest period of their discovery, have been compared 
or identified with the locomotive monads, the products of the en- 
cysted stage in many of the Protozoa. 
The essential difference between a spermatocyst and its homo- 
logue among Protozo6a consists in the fact that the latter has to 
become a full-grown feeding zodn before it is ripe, and proceeds 
to produce by division secondary males, which seek out the & 
male for the purposes of impregnation, while the latter, as its de. 
scendant, has acquired by concentration of development, the same 
powers and habits in its earliest stage, and its sole function is to 
become encysted and produce larval male cells for the impregn 
tion of the female zobn or ovum. The impregnation in both 
cases immediately precedes the reorganization of the nucleus of 
the female (ex. Vorticella), and are followed by a period of repro 
duction by division, which is infinitely more concentrated in the 
encysted ovum, as an encysted larval form, than in the free adult 
Protozoén. The former is thus a builder of close-set tissues oo 
posed of larval cells, and the latter of loosely associated colonies 
of adult feeding zodns. 
A’ 
se 
THE NATURALIST BRAZILIAN EXPEDITION 
Parer III.—SAo João po MontE NEGRO. 
BY HERBERT H. SMITH. 
run up this river from Porto Alegre nearly every day, 
at the various German colonies along the banks, pei 
down mandioca-meal, corn, beans, tobacco and other esr 
The Cahy is very crooked, and the lower portion 1$ 4 oftet 
by a wide flood-plain. The clay banks are steeply cat, eP the 
thirty feet high, so as to be beyond reach of all ae heavy 
strongest floods. They are covered in many places her anche 
forest, leguminous trees and myrtles being abundant a are oft? 
are draped with vines, and palms of one or twO kin 
