206 
sified an order, must be expected to be comparatively few; those 
which I have observed in the skull are as follows :— 
The tuberosity of the maxillary bone is articulated by the whole 
of its upper surtace to the frontal and orbitosphenoid bones. 
The zygoma is flat and straight, projecting at once outwards and 
forwards, its articulating surface being more or less confiuent with a 
concavity at the inner side of it which forms a portion of a more or 
less elongated cone, whose apex would point backwards. In such 
forms as have the articulation longitudinal, the glenoid surface is 
distinguishable from that of Rodents by its posterior termination, 
which is not a thin free edge like the anterior. 
The alisphenoid bone never extends high, so that the pterygoid 
ridge forms its upper boundary, or even extends above it. 
The absence of enamel in the teeth, when they exist, must also be 
named among the cranial characters. 
Fam. 1. BrapyPopIDz. 
The intermaxillary bones confined to the lower part of the nasal 
opening ; the maxillary bones provided with simple teeth, shortened, 
their malar processes much pushed forwards upon them, and the 
molar series converging behind ; the posterior palatine foramina re- 
placed by a series of minute openings extending the whole length of 
the palate ; the malar bone having a descending masseteric process 
transversely compressed, longitudinally extended, and with a di- 
stinct superadded process arising between its frontal and zygomatic 
processes ; the foramen rotundum distinct, and opening exteriorly at 
the base of the pterygoid process some distance below the spheno- 
orbital foramen and anterior to the foramen ovale; the zygoma 
straight and trigonal, its origin thick and extensive, reaching back 
quite to the posterior part of the squamous bone; the mastoid bone 
with a wide digastric fossa, and a strong thick styloid process, ter- 
minating in a circular concavity for the reception of the stylohyal 
bone ; the lower jaw widened anteriorly with an extended symphysis. 
Tt must be observed that the superadded process of the malar bone 
is peculiarly characteristic of this family, and is quite distinct from 
any of the processes of that bone to which special names have been 
assigned. It is situated between the frontal or postorbital and zygo- 
matic processes, both of which seem also to exist in a more or less 
rudimental form in most of the known species ; and when the latter 
is wanting as in the genus Cholepus, the fact that the new process 
stands aloof, above the zygoma, is enough to prevent its beg taken 
for the zygomatic process, which in all mammalia possessing a com- 
plete zygomatic arch either abuts simply against the extremity of the 
zygoma, or more generally seems to support it from beneath. 
The zygomatic process is well developed in the Megatherium, and 
completes the arch, leaving the other, which might be called the 
supratemporal process, projecting above it. In Mylodon robustus 
the frontal process is reduced to a slight angle upon the base of the 
supratemporal process. In the Scelidotherium the process existing 
