The Urogenital Organs 195 
them, on the side towards the upper wall of the 
cloaca, a fairly deep furrow that extends to the tip. 
According to Rathke these shafts are not of cavern- 
ous tissue, but the tube is lined by a layer of this 
tissue. 
The glans, e, consists of two parts between 
which, where they leave the shaft of the penis, is 
a funnel-shaped hole, wider towards the free end 
of the penis and divided into similar lateral halves 
by a fold of skin. The glans is much shorter than 
the shaft of the penis. The covering of the penis 
is much thinner than the mucous membrane of 
the cloaca and is thinnest along the groove; it 
extends from the shaft over the glans without 
forming a foreskin. 
The base of the penis is attached to the pubis 
near its symphysis. With this base the most 
anterior part of the strong ring-muscle of the 
cloaca is closely attached by a fairly large mass of 
fibrous tissue. Rathke fails to find any muscles 
that are concerned alone with the copulatory 
organs. 
In the copulation of the crocodile, according to 
Rathke, the penis is erected, though how this is 
caused is difficult to say since the corpora cavernosa 
consist only of fibrous tissue and the cavernous 
tissue lining the groove is very thin. The penis 
can, therefore, project only a short distance from 
the cloaca. The cavernous tissue is capable of 
causing only a slight elongation of the shaft, but 
