56 THE SKELETON OF THE CAT. 
large jugular foramen (/), for the ninth, tenth, and eleventh 
nerves. Opening into the mediocaudal margin of the jugular 
foramen is the smaller hypoglossal foramen, for the twelfth 
nerve. 
The craniomedial end of the tympanic bulla projects craniad 
as the styliform process (2). Just laterad of this process is the 
opening (7) into the tympanic bulla by which the tuba auditiva 
or Eustachian tube passes into the middle ear. A faint groove 
for the tube passes craniomediad from this opening, on the sur- 
face of the sphenoid. Craniolaterad of the opening for the tuba 
auditiva is the foramen ovale (4); craniad of this the foramen 
rotundum (/) is faintly indicated. On the surface of the 
sphenoid just craniad of the styliform process of the bulla tym- 
pani is the minute opening of the pterygoid canal (¢). The 
orbital fissure and optic foramen are not seen in the ventral 
view. 
The middle region of the ventral surface is narrow: it is 
formed by a trough-like fussa which is bounded laterally by the 
pterygoid processes (77) of the sphenoid and the perpendicular 
plates of the palatines (wz). Ventrad of this lies, in the natural 
condition, the soft palate, converting the fossa.into the nasal 
portion of the pharynx or nasopharynx. Craniad this fossa is 
bounded by the free caudal edges of the palatines; beneath 
which the fossa communicates with the nasal cavity by the two 
choane (0). lLaterad of this median fossa are visible in the 
ventral view parts of the temporal and orbital fosse, bounded 
laterally by the zygomatic arches (). 
The cranial part of the ventral surface is a somewhat tri- 
angular plane area formed by the palatal portions of the pala- 
tines (8), maxillari2s (9), and premaxillaries (10), which together 
constitute the hard palate (palatum durum). Laterad and 
craniad this area is bounded by the alveolar borders of the 
maxillaries and premaxillaries bearing the teeth. The hard 
palate is marked near the cranial border of the palatine bones 
with two or more foramina which form the cranial termination 
of the posterior palatine canal (7). Two faint grooves pass 
from these foramina a short distance craniad, gradually con- 
verging: these are known as the palatine grooves (7) (sulci 
