em 
cessory glans as is that of the ram, and the urethra preserves a me- 
dian course until it passes to the papilla on the left side. The ex- 
ternal characters of the penis in the Musk-Ox have been recently de- 
scribed by Dr. Eryar LONNBERG!). Here the urethral tube extends to 
the end of the penis, though the portion not fused with it is short. 
It comes off from the left side like the urethral papilla in the bull. 
Dr. LÖnNBErG after referring to the fact that a filiform extension is 
present in so many Ruminants says: “it may be concluded that this 
is an ancient characteristic (of the group), and the ancestors of 
Ovibos probably had a similar organ.’ The same remark applies 
equally to the ancestors of Bos, and it may be added that since the 
papilla on the penis of Bos occupies the same position as the point 
of attachment of the filiform appendage in Ovis, that the penis in 
the ancestors of Bos was of the ovine type. The urethral papilla, then, 
in Bos is of the nature of a vestige. The absence of the filiform 
appendage in some Ruminants, while it is present in closely allied 
forms is difficult to explain. LÖNNBERG, writing of the Musk-Ox says: 
“Such a thin filiform termination of the urethra must easily be damaged 
by frost, and it could hardly be useful to an animal living in such a 
cold climate that it needed even the interior of the praputial sac 
clothed with hairs or wool.” This, however, does not explain how the 
need, supplied in other Ruminants by a filiform termination of the 
urethra, is supplied in Ovibos, and the explanation, such as it is, 
cannot apply to Bos and the Bubaline Antelopes, in which, as LOnN- 
BERG himself observes, the filiform appendage is absent also. The 
presence or absence of the appendage, must be directly related to 
the chances of the sperms otherwise reaching their destination, these 
depending probably on the quantity of seminal fluid and the size of 
the uterine passage. 
The figures illustrating this paper were drawn by my friend Mr. 
F. M. HowLerr. 
1) Lönngeng, On the soft Anatomy of the Musk-Ox. Proc. Zool. 
Soc. London, 1900, Part I. 
