SKELETON OF CAENIVORA. 495 



overarched by a thickly-developed occipital ridge ; the squamosal 

 and malar rise abruptly at their junction at the middle of the 

 zygoma. The acoustic bulla receives the meatus auditorius by 

 an expanded and oblique opening. The olfactory fossa3 contain, 

 as in all Seals, large and complex turbinal bones. The bony 

 palate is terminated behind by a semicircular notch. 



In the Monk Seal (^Pelagius monachus) the upper contour of 

 the skull presents a sigmoid curve. The temporal ridges meet, 

 and form a low sagittal crest over the posterior half of the 

 frontals and parietals. The upper jaw is much less deep than in 

 the Haliclioerus, the canines are relatively larger and the nasal 

 bones are much shorter. The entocarotid canal perforates the 

 back part of the petrosal as in the Phoca grcenlandica : the ecto- 

 carotid does not pierce the pterygoid process. 



In the Sterrinks {Stenorhi/jichus) the skull is longer, more 

 ' canine ' in the proportions of jaws to cranium, than in other 

 Seals. The malar is long and slender, defining the orbit below : 

 a lacrymal process of the maxillary projects from the anterior 

 rim. The basis cranii is long and narrow in Stenorliyncus lept- 

 onyx. In the saw-toothed Sterrink {Stenorhynchus serridens) 

 the facial part tapers more gradually than in the Stenorhynchus 

 leptonyx. The paroccipitals are small, but distinct. The pe- 

 trosals are perforated posteriorly for the entocarotids ; the 

 pterygoid processes are imperforate. The temporal ridges meet 

 upon the sagittal suture, but do not develope a crista. The malar 

 bones are slender, strongly curved, bifurcate posteriorly, the 

 upper prong rising to form, mth the zygomatic process of the 

 squamosal, the postorbital boundary. There is no corresponding 

 process from the frontal. The antorbital process of the maxillary 

 is small, but distinct. The premaxillaries are narrow and slender, 

 but do not reach the nasals. The posterior border of the bony 

 palate is terminated by a deep semi-elliptic notch. A single 

 superoccipital venous canal opens, in Sten. lej^tonyx, within the 

 border of the foramen magnum. The basioccipital shows two 

 depressions. The sella turcica is very shallow, and is defined 

 only by a posterior clinoid ridge, between which and the platform 

 for the optic chiasma there is a long tract. The petrosals termi- 

 nate by obtuse subdepressed apices. The foramina lacera anteriora 

 are of unusual size, and appear to include the foramina rotunda : 

 there is no ridge indicating the division between the anterior and 

 middle lobes of the cerebrum. The rhinencephalic fosste are small, 

 but deep and well defined, and completely divided by a broad and 

 thick crista galli. 



