334 PROF. HUXLEY ON ARCTOCEBUS CALABARENSIS. [June 28, 
rentia and those of the ureters; but careful examination did not re- 
veal the existence of any such structure. Two longitudinal folds of 
mucous membrane, along which the apertures of the prostatic ducts 
(Pr, fig. 12, B) are situated, extend from the colliculus and form 
the lateral boundaries of a wide fossa, which it overhangs. This 
fossa receives at its upper and back part, by two separate apertures, 
the ducts of two large oval sacs, which are perfectly distinct from 
one another, though their inner walls are united for some distance. 
The walls of these sacs are raised into oblique folds, and they lie at 
the back of the neck of the bladder behind the vasa deferentia, and 
occupy the place of the vesiculz seminales. As they do not com- 
municate directly with the vasa deferentia, however, I am doubtful 
whether they ought to be considered as representing the vesicule 
seminales, or as a large uterus masculinus. 
These sacs are distinguished externally from the prostate (Pr) 
only by a slight constriction; but their ducts pass in front of that 
gland, which lies altogether at the back of the urethra, ‘so that the 
front wall of the latter is free and uncovered by the prostate. The 
prostate is pyriform, broad above, narrow below, and has the ordi- 
nary structure. - 
A “membranous portion” of the urethra unites the prostatic 
part with the slightly dilated bulbous portion and its continuation 
lodged in the corpus spongiosum. ‘The bulb receives the ducts of 
the two large oval Cowper’s glands (Cp, figs. 11, 12), each of which 
has thick walls and a central cavity continuous with the ducts. 
The os penis, 0°75 inch long, is situated between the corpora caver- 
nosa, extending from the apex of the penis backwards in the middle 
line. 
The glans penis consists of a median, curved, subcylindrical portion 
supported by the extremity of the bone of the penis, and of a sort of 
hood, bifid below, which surrounds the base of this. The hood has 
a tuberculated surface ; and the urethra opens between the lobes 
formed by its inferior bifurcation, and therefore at some distance 
behind the apex of the organ. 
According to Van der Hoeven’s account (/. ¢. p. 54), the male re- 
productive organs of the Potto must be very similar to those of the 
Angwantibo ; and Kingma’s description and figures demonstrate the 
like for Otolienus peli. Kingma, in fact, has worked out the ana- 
tomy of the parts more thoroughly than Van der Hoeven; for he 
shows that, as in the Angwantibo, the hollow vesicles connected with 
the prostate open independently of it and of the vasa deferentia, 
and does not admit them to be vesiculee seminales. But it is unsafe 
to come to a conclusion respecting the nature of these parts without 
some knowledge of their development. 
In his recently published “ Revision of the Species of Lemuroid 
Animals”’ (Proce. Zool. Soc. 1863, p. 129), Dr. J. E. Gray has sepa- 
rated the Angwantibo from Perodicticus, and has made it the type 
of a new genus, Arctocebus. The genera Perodicticus and Arcto- 
cebus are differentiated as follows (7. ce. p. 150) :—~ 
