OSTEOLOGY OF THE HYOPOTAMIDiE. 
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part, and inclined to the outer side; its upper margin is rugose, but presents no 
flattening or expansion, as in many Ungulates of the Imparidigitate series. The pars 
acromialis is produced forwards in the same way as in Anoplotherium , the Camelidce , 
and most Ruminants, hut never in Pigs, where the spine rises very slowly from the neck 
backwards without any trace of an acromial process. The rising of the spine above 
the surface in Ilyopotamus commences at a distance of 30 millims. from the glenoidal 
border; but the acromion is so produced forward that it reaches nearly to the level of 
the glenoidal cavity, overarching the neck of the bone. The supraspinous is a little 
smaller than the infraspinous fossa, but the difference is not important. 
In considering the very great breadth of the scapula of Ilyopotamus , we must not 
forget that all Ungulatahave a very large upper cartilaginous border, which is wanting 
in our fossil : the scapula figured by me belonged to a young individual ; and we may 
safely infer that by the gradual ossification of the cartilaginous upper margin, the 
breadth would not be so disproportionate to its length as it is now. On the outer side 
of the neck of this scapula we see a pretty deep and large elongated fossa, found also on 
two other broken specimens. In general shape this fossil scapula agrees most with 
the scapula of Hippopotamus , by its great breadth and by the production of the acromial 
extremity of the spine, in which respect it also closely approaches some ruminants. 
With the Suinte, however, we find no relation at all ; and I particularly insist on this 
point, as, owing to the poorness of the Paridigitate types in our recent fauna, we are 
very apt, whilst studying fossil Mammalia with unreduced skeleton, to find resemblances 
with Suinge even where they are very slight, just because the pig has one of the most 
complete (unreduced) skeletons among the living Ungulata. 
Unfortunately I could not find in the collection of M. Aymard, nor in that of the 
Puy Museum, a scapula of Ilyopotamus. 
Dimensions of the Scapula of Hiplopus AymardL 
millims. 
Height of the articular fossa 34^ 
Transverse breadth of the articular fossa 37 
Height of the spine 31 
Transverse breadth, including the coracoid process ... 57 
Breadth of the neck 47 
Largest transverse diameter 190 
Whole length 218 
This was written and my Plates were drawn in London in the summer ; but having in 
November last paid another visit to Puy, in order to examine the collection of Mr. Vinay, 
which I was prevented from seeing on my first visit, I found there a very good speci- 
men of the scapula of Hyopotamus. The upper margin of the bone was broken, and 
only about two thirds remained entire; the spine of the scapula was preserved, although its 
acromial part was broken ; and I could not ascertain if it was prolonged forwards in 
