118 
MR, W. K. PARKER ON THE STRUCTURE AND 
the skull of the Edentata. But for what is seen in Orycteropus, I should leave 
the Marsupial type of skull out of question in the present comparison. All the New 
World kinds, and the Pangolins of the Old World, may be considered in relation to 
each group—to the Monotremata below them, and to the Insectivora above, or rather 
outside, them. 
As far as I can see at present, the parietals coalesce very early in the Monotremes, 
and the large supraoccipital grows over to meet this quasi-reptilian roof, and form 
the lambdoidal suture. 
In the Edentata the parietals do not meet and coalesce early ; but the supra¬ 
occipital region is very large, turns over towards the parietals, and ossifies early, and 
has no interparietal separating it from the parietals. 
This takes place in all but Orycteropus, which has one of the largest inter- 
parietals I have seen, and thus agrees with Marsupials, Insectivora, and the Mammalia, 
generally, that have normal teeth. 
The premaxillaries are very small in the Edentata, especially those that are abso¬ 
lutely toothless ; Orycteropus has the best developed premaxillaries of any of the 
members of this Order. The maxillaries have the best development in Orycteropus, 
and the feeblest in the Pangolins ; and they and the little Anteater ( Cycloturus ), have 
only the rudiment of a jugal. That bone, although large, does not make a finished 
zygomatic arch in the Sloths ; it does in the Armadillos ; it is quite normal in 
Orycteropus. The most Crocodilian development of the hard palate takes place 
in the Ant-bear and the Tamandua; in Cycloturus the pterygoids go quite as far back 
as in the large kind, and are attached to strong basipterygoid processes of the basi- 
occipital bone. In the Sloths, especially Cholopus didactylus, C. Hoffmanni, and 
Bradypus tridactylus, the pterygoids are vepv large and long, and in the last kind 
form a great “ antrum ” on each side. The basioccipital bones have considerable 
basipterygoid processes with no bones attached to them. 
In Dasypus, the Manidae, and in Orycteropus , the pterygoid bones are quite normal, 
but in the genus Tatusia, amongst the Dasypodkke, the short, thick pterygoids add 
somewhat to the hard palate. 
The lacrymal is absent in the Pangolins, huge in the Aard-Vark and Armadillos, 
and smallish in the Anteaters and Sloths. 
The squamosal is pneumatic in all these types, adding a considerable upper gallery 
to the tympanic chamber; this agrees well with what is seen in Marsupials and 
Insectivores. 
The os tympanicum is feebly developed in all the Edentata, about equal to what 
we see in Marsupials and Insectivora, but in none is there any such enlargement of 
the drum cavity as is seen in some Marsupials, and a few Insectivora, formed by a 
growth of the alisphenoid and a large “os bullae;” nor from a special wing of the 
basisphenoid, as in the Hedgehog and Tenrec. 
Where there are several teeth, as in Armadillos and the Aard-Vark, then the stapes 
