LEPUS. 393 
canines and molars) and thecodont (in sockets) teeth, 
axial, the bony palate formed of bony expansions of 
* the maxillze and palatines meeting in the middle 
line, two occipital condyles upon the exoccipitals, the 
suspension of the lower jaw by the squamosal, the single 
bone of the lower jaw and the three auditory ossicles. 
The large size of the nasal chambers and nasal bones, 
the incomplete ossification of some bones, such as maxillee 
and occipitals, the confluence of orbit and temporal fossa, 
and, above all, the character of the dentition, are features of 
the order Rodentia, whilst the presence of small second upper 
incisors and other lesser features are characteristic of the 
sub-order containing rabbits and hares. 
The cranium of the skate could be recognised as formed 
of the cranium proper and the cartilages of the three 
sense-capsules. Similarly the bones of the rabbit’s skull 
can be correlated with the cranium proper and the sense- 
capsules. 
The former are arranged more or less in rings around 
the cranial cavity which facilitates their recognition. 
The occipital ring is the most posterior. In many skulls 
it may be completely detached from the others. It is 
formed of a supraoccipital, paired exoccipitals and a dbast- 
occipital, 
The sphenoid ring is formed of paired parietals above 
(and a small znterparietal), paired alisphenoids laterally and 
a basisphenotd. 
The presphenoid ring has a pair of frontals above, a pair 
of orbitosphenoids laterally and a presphenoid below. 
The ethmoid ring has a pair of nasals above, a mes- 
ethmoid below, which lies between the two nasal chambers 
and broadens out posteriorly to form the cribriform plate, 
and a perforated bony septum between the cranial and 
nasal cavities. 
The bones of the sense-capsules are closely united with 
those of the cranium proper. The auditory bones lie 
between the occipital and sphenoid rings. ‘They consist 
of a feriotic containing the inner ear and produced into a 
prominent mastoid process, and the ¢ympanic which is swollen 
into a hollow auditory dw//a and produced upwards there- 
from as a bony auditory meatus. The eyes are embedded 
