. 
364 PROF. W. H. FLOWER ON THE EDENTATA.  ([Apr. 18, 
mecophaga and Megatherium ; but in the peculiar form and ankylosis 
of some of the cervical vertebrae, common to all existing members of 
the family, it stands apart from all other Edentates. In the presence 
of a clavicle it resembles the other American forms ; but it differs in the 
shape of the scapula, and in the existence of a third trochanter to the 
femur. The structure of the extremities, especially the manus, presents 
many modifications, some of which are quite comparable to, though not 
identical with, those of the Myrmecophagide. 
The reproductive organs differ in the presence of a largely de- 
veloped copulating organ in the male, and of a simple vagina of cor- 
responding length in the female; these, as long ago suggested by 
Professor Owen, appear to be correlated with the difficulties which 
would otherwise be interposed to sexual congress by the arrange- 
ments of the dermal armour, and which of course do not occur in 
the Sloths and Anteaters. The testes are still abdominal, though 
not in the same position; and the penis, notwithstanding its size, 
wants (as pointed out by Morrison Watson’) both the glans and 
bulb, generally formed in mammals by the corpus spongiosum. The 
uterus is as simple, or nearly so, as that of the Sloths wnd Anteaters ; 
and there is no reason to suppose, from what is at present known, that 
the placentation differs in principle from that of those families ; for if 
deciduate, whether the whole mass assumes an oval, discoidal, or 
bell-shaped form is only a matter of detail. 
The Armadillos, then, have undoubtedly near affinities to the 
other American Edentates, and are probably members of the same 
group, though not so nearly related to either of the other families 
as they are to each other, and are moreover remarkably specialized 
in a particular direction. The Glyptodonts form an allied group, 
agreeing in most essential features, but also presenting some very 
singular special modifications. 
Lastly, Orycteropus is a form in most respects perfectly apart 
from all the others. The structure of its teeth alone would almost 
entitle it to be placed in an order by itself, were it not for the 
practical inconvenience of doing so. Its vertebral column is formed 
on the normal type of mammals. Its limbs also present com- 
paratively few specializations ; but it resembles the Armadillos in pos- 
sessing a third trochanter to the femur. Its digestive organs are 
also comparable to those of the Armadillos, as its mode of feeding 
is similar. But its reproductive organs, both male and female, and 
placentation are formed upon a principle unknown in other Eden- 
tates, or, in combination, in other mammals. The testes, in a specimen 
I once examined, were inguinal, though they appear to descend, at all 
events temporarily, into a scrotum; but the penis is almost as small 
as in the Great Anteater. The uterus is more bicornuate than in 
Manis, the two lateral chambers opening separately into the vagina, 
as in some Rodents. The placenta, as described by Prof. Turner, 
is broadly zonular; but whether deciduate or not is at present un- 
determined, probably the latter. As Balfour remarks, this type of 
placenta is capable of being easily derived from that of Munis, 
1 PZ. 8. 1878, p. 677. 
