ORYCTEROPODIDE 209 
in the centre, from which the dentinal tubes radiate outwards, and 
- being closely packed together each system assumes a polygonal 
outline as seen in transverse section. The small anterior teeth have 
milk-predecessors which are fully noticed below. Skull moderately 
elongated. The facial portion subcylindrical and slightly tapering. 
The zygoma complete and slender. The palate ends posteriorly in 
the thickened transverse border of the palatines, and is not 
continued back by the pterygoids. The tympanic is annular, and 
not ankylosed to the surrounding bones. The mandible is slender 
anteriorly, but rises high posteriorly, with a slender recurved 
coronoid, and an ascending pointed process on the hinder edge 
below the condyle, which is small, oval, and looks as much forwards 
as upwards. Vertebre: C7, D13, L8, 86, C27. The large 
number of lumbar vertebre is peculiar among Edentates. Tongue 
less vermiform than in Alyrimecophaga, being thick and fleshy at the 
base, and gradually tapering to the apex. The salivary apparatus 
is developed much in the same manner as in that genus, but the 
duct of the submaxillary gland has no reservoir. The stomach 
consists of a large subglobular cardiac portion, with a very thick, 
soft, and corrugated lining membrane, and a smaller muscular, 
pyloric part, with a comparatively thin and smooth lining. There 
is a very distinct ileo-cecal valve, and a considerable-sized cecum ; 
also a gall-bladder. Head elongated, with a tubular snout, terminal 
nostrils, and small mouth-opening. Ears large, pointed, erect. 
Tail nearly as long as the body, cylindrical, very thick at the base, 
tapering to the extremity. 
The reproductive organs and placentation of Orycteropus are 
formed upon a principle unknown in the more typical Edentates, 
or, in combination, in any other mammals. Thus the testes, in the 
one described example, were inguinal, but appeared to descend, at 
all events temporarily, into a scrotum; but the penis is scarcely 
larger than that of the Great Anteater. The uterus is still more 
fully bicornuate than in J/unis, with its two lateral chambers 
opening separately into the vagina, as in certain Rodents. The 
placenta is broadly zonary, but it is not known whether it is 
deciduate or not. It might readily be derived from the diffused 
placenta of A/unis by the abortion of the foetal villi at the two poles 
of the ovum. 
The Orycteropodide have long been regarded as widely different 
from other Edentates, their presumed affinity with the J/anide 
being more or less problematical ; but the discovery recently made 
by Mr. O. Thomas? that they have a milk-dentition still further 
emphasises their aberrant nature. According to this observer, it 
appears that there are normally no less than seven milk-teeth in the 
upper jaw, the hindmost of which is far larger than the others, 
1 Proceedings of the Royal Society, vol. xlvii. p. 246 (1890). 
14 
