g6o Mr. Home's Description of the Anatomy - 
and therefore are not so nearly allied to the Ornithorhynchus 
as I had at first been led to imagine. The Myrmecophaga jubata, 
which is described by Mr. Zan to have the organs of genera- 
tion, in both sexes, concealed within the verge of the anus, 
appears to be a nearer approach to it than the other species. 
The peculiar characters of the Ornithorhynchus, as a genus, 
or more properly a tribe of animals, are, 
The male having a spur on the two hind legs, close to the 
heel. 
The female having no nipples. 
The beak being smooth, while the rest of the animal is co- 
vered with hair. 
The tongue having horny processes, answering the purposes of 
teeth. 
The penis of the male being appropriated to the passage of 
the semen ; and its external orifice being subdivided into several 
openings, so as to scatter the semen over an extent of surface, 
while the urine passes by a separate canal into the rectum. 
The female having no common uterus ; and the tubes which 
correspond to the horns of the uterus in other quadrupeds, re- 
ceiving the semen immediately from the penis of the male. 
These characters distinguish the Ornithorhynchus, in a very 
remarkable manner, from all other quadrupeds, giving this new 
tribe a resemblance in some respects to birds, in others to the 
Amphibia ; so that it may be considered as an intermediate link 
between the classes Mammalia, Aves, and Amphibia ; and, al- 
though the great difference that exists between it and the Myr- 
jnecophaga, the nearest genus we are at present acquainted 
with, shows that the nicer gradations towards the more perfect 
quadrupeds are not at present known, the facts which have 
