North American Lizards. 
35 
cells. The gonads or germ glands, accordingly, their seats of growth 
and multiplication, should promise to be conservative structures. In 
fact they are, and only unimportant microscopical differences were 
found between the ovaries of the different genera, or between the 
testes. 
The vasa deferentia vary in complexity of convolution, but this, 
like the convolution of the oviducts, may well vary temporarily ac- 
cording to the state of the sexual activity. In all the genera studied 
their posterior apertures are disconnected, and each opens conjointly 
with the ureter of its side upon a cloacal papilla. Seminal vesicles, 
a dilation of the posterior part of each vas deferens, were found in all 
but Eumeces and Gerrhonotus. 
The oviducts also always open conjointly with the ureters. But 
while in Sceloporus, Holbrookia, Plirynosoma, Crotaphytus and 
Eumeces the opening of the right oviduct is always separated from 
that of the left, in Gerrhonotus and Cnemidophorus they are united; 
the latter is clearly a secondary modification. In the last two genera 
also, as well as in Eumeces, another specialization appears, namely, 
a muscular sphincter around the posterior ends of the oviducts. 
A urinary bladder is present in both Eumeces and Gerrhonotus, 
but completely absent in the. other genera studied. This is in disagree- 
ment with the statement of Cope (1900) , “ urinary bladder generally 
present. ’ ’ 
Adrenal glands are present in all, though sometimes unpaired. 
Histological study shows them to be composed of sympathetic nerve 
cells as well as of glandular tissue. Whether they represent inter- 
renals or suprarenals, or both, appears to have been not yet satis- 
factorily determined by embryologists ; on this question one may com- 
pare the papers of Braun (1879), Howes (1887), Leydig (1853) and 
Petit (1896). 
It may be found that the lobulation and degree of posterior exten- 
sion of the kidneys will furnish characters of phylogenetic import. 
In Holbrookia, Sceloporus and Crotaphytus these organs are nearly 
smooth, without lobes, and extend for a considerable distance pos- 
terior to the anus. Plirynosoma differs only in having the kidneys 
slightly notched along their lateral edges. In Eumeces each kidney 
consists of two large lobes, an anterior larger one, and a posterior 
one that extends behind the anus. In Gerrhonotus each is composed 
of a large anterior lobe and several smaller posterior ones, none of 
which extend behind the anus. Finally in Cnemidophorus each kid- 
ney is essentially unilobar, with simply a connective tissue extension 
beyond the anus. The differences in kidney configuration agree 
with other family differences. The extension of the kidneys behind 
