REPRODUCTIVE HISTORY OF THE MOLE. 207 
sinus. As the urinary passage passes from the bladder towards 
the urethral outlet at the tip of the genital tubercle it describes 
a curve of which the convexity is directed caudad: it is at the 
lowest part of this bend that the female genital ducts terminate 
in the urethra. The Mullerian ducts pass down dorsal to the 
bladder and urethra, and then running ventrally with a curve 
similar to that of the urethra, they terminate at the caudal floor 
of the urethral bend. 
This termination is made in the immediate neighbourhood of 
the orifice of the Wolffian ducts, and a considerable proliferation 
of epithelium marks the actual site of the ends of the ducts of 
Muller (PI. I. figs. 1 & 2). 
In the embryo of 27 mm. the continuity of the Mullerian 
ducts and the urethral passage is easy to trace, although the 
proliferation of the Mullerian epithelium makes the continuity of 
the lumina difficult to establish with certainty. 
So far this must be considered merely as a primitive arrange- 
ment in which separate Mullerian ducts terminate in a uro- 
genital sinus in the neighbourhood of the Wolttian ducts ; and 
the peculiarity which exists in Zalpa at this stage is that the 
uro-genital sinus is closed in, and carried forwards to the tip of 
the genital tubercle, in the female as it is in the male. Were it 
not for this penile prolongation of the female uro-genital sinus, 
there would be nothing very remarkable in the primitive 
condition of Zalpa at this stage. 
Even in this peculiarity Zalpa is not unique; for very similar 
conditions are known to be present in some other animals. 
Among Insectivores several species have been described as 
having the genital tubercle tunnelled by the urethra in the 
female; this condition occurs again among the Lemurs, and, 
according to Chapman, Capromys pilorides among the Rodents 
shows a like conformation of the clitoris in the female. Tn all 
these types, however, the Mullerian ducts open in the normal 
way by a separate vagina, and no great physiological questions 
are raised by this anatomical arrangement. But the condition 
described by Morrison Watson (9) and by Chapman (10) in 
Hyena crocuta appears to be an exact parallel to the virgin 
condition of Zalpa. Assuming that it is not by the mere 
coincidence that only virgin examples of Hycna crocuta have 
ever been examined by anatomists, we must suppose that the 
condition in this case is permanent; that no new vagina is ever 
formed; that copulation takes place via the urethra, and that the 
young are born by the same route—through the tip of the 
clitoris. 
In Talpa it is evident that this primitive condition does not 
last long, for already in the embryo of 33 mm. the Mullerian 
epithelial proliferation has proceeded a stage further and the 
lower ends of the Mullerian ducts are somewhat more separated 
from the wall of the urinary passage. The condition seen at this 
stage is as follows. The Mullerian ducts which above are united 
