502 ANATOMY OF VEKTEBEATES. 



occipital connects together the two condyles : the temporal ridges, 

 commencing from the postorbital processes, meet at an open 

 angle, and extend backward, as a low and straight sag-ittal crest, 

 as far as the broader occipital crest. The zygomatic arches are 

 strong and boldly curved ; they bifurcate anteriorly to surround 

 the large antorbital foramen. The cranial walls are thin, >vithout 

 diploe : the impressions of the convolutions are strongly marked : 

 there are no frontal sinuses. The cranial cavity is remarkable 

 for its great posterior expanse and its extreme contraction be- 

 tween the prosencephalic and rhinencephalic divisions. The bony 

 tentorium terminates upon the petrosal above the small pit for the 

 cerebellar appendage. The sella turcica is shallow. The tract 

 for the optic chiasma is long and narrow. The crista galli 

 extends backward through nearly the whole of the rhinencephalic 

 fossa. The longritudinal sinus communicates behind with two 

 small venous foramina in the superoccipital bone. The olfactory 

 chamber commences directly in front of the rhinencephalic fossa, 

 the cribriform plate, or back part of the olfactory capsule with 

 the coalesced prefrontals, separating them. The entry to the 

 nasal passages is almost blocked up by the large and complex 

 turbinals. 



In the Civet ( Viverra Civetta), the occipital condyles are sepa- 

 rate from each other at their lower extremities. The paroccipitals 

 and mastoids have coalesced and form a triangular plate of bone, 

 applied to the posterior part of the tympanic bulla, like the cap- 

 sule of the acorn to the seed. This bulla is more circumscribed 

 and mucli more developed than in the Otter : the bony meatus 

 auditorius is much shorter, and opens directly into the tympanic 

 cavity. The nasal processes of the upper maxillaries extend 

 backward much further than the nasal bones, tlie reverse being 

 the case in the Otter. The pterygoid processes are perforated 

 by the ectocarotids. The cranial cavity is longer and narrow^er, 

 and the postorbital constriction much less, than in the Mustelidos. 

 The bony tentorium is continued forward beyond the petrosal, 

 and terminates above the foramen rotundum. The petrosal is 

 impressed by a deep pit for the cerebellar appendage. A ver- 

 tical inverted tract of the cranial walls divides the prosence- 

 phalic from the rhinencephalic compartments. The olfactory 

 fossa is continued backward above as w^ell as beneath the 

 rhinencephalic compartment. The crista galli is rudimental. 

 When the squamosal is removed, the extensive surface of the 

 parietal and alisphenoid is exposed to which it v> as applied, and the 

 small vacuitv in the suture between those bones which was left 



