52 THE SKELETON OF THE CAT. 



A portion of the floor of the orbit and the opening of the 

 lachrymal canal (o) may also be seen in dorsal view ; they are 

 described in connection with the lateral surface. 



The caudal surface of the skull is formed largely by the 

 occipital bone (Fig. 17), surrounding the foramen magnum 

 (Fig. 17, d}. At the sides of the foramen magnum are the 

 two prominent curved occipital condyles (e) for articulation 

 with the atlas. Craniolaterad of the condyles, separated from 

 them by a deep notch, are the jugular processes (/) of the 

 occipital, closely applied to the caudal ends of the tympanic 

 bullae. 



Dorsad of the foramen magnum are faint indications of a 

 median ridge running dorsad, the external occipital crest 

 (Fig. 17, z); this rises at its junction with the lambdoidal ridge 

 to form the prominent external occipital tubercle (Fig. 39, b). 

 The dorsal and dorsolateral boundaries of the posterior surface 

 are formed by the lambdoidal ridge (Fig. 17, //; Fig. 39, a). 



The lateral surface of the skull (Fig. 40) is much more 

 complicated than the dorsal and posterior surfaces. Caudally 

 the occipital condyles (a) and external occipital crest (fy are 

 visible; dorsocaudad the sagittal crest (r). 



Extending from the caudal end of the sagittal crest the 

 lambdoidal ridge (d] is seen passing ventrocraniad to the tym- 

 panic bulla, thence craniad to the root of the zygomatic arch. 

 In the ventral part of the caudal region the tympanic bulla (e) 

 is visible with the jugular process (f) of the occipital pressed 

 close against its caudal end. Just craniad of the jugular process 

 the mastoid process (g) of the temporal rests against the side 

 of the bulla. Beneath the cranial edge of this process is the 

 opening of the stylomastoid foramen (/i) for the seventh nerve, 

 while just ventrad of the foramen is the small pit (z) in the 

 tympanic bulla for the reception of the tympanohyal bone. 

 Craniad of the stylomastoid foramen is the large opening of the 

 external auditory meatus (/), leading into the middle ear. 



Immediately dorsocraniad of the external auditory meatus 

 the zygomatic arch begins as the zygomatic process (fc) of the 

 temporal bone. On the cranial surface of the base of this 

 process is the deep mandibular fossa (/) for the condyle of the 



