1536 Cetacea. 



however, advance as far as the base of the occipital crest, following 

 up the superior edge of the frontal bone. 



Parietal bones soldered to the upper part of the temporal bones, 

 and beneath the superior apophysis of the superior maxillaries. 



The occipital bone advances towards the base of the intermaxilla- 

 ries ; its crest, which is very little developed, unites the two tempo- 

 ral crests. The occipital bone is depressed and concave superiorly, 

 then convex, and after this sloping off gradually to the occipital 

 hole. The condyles are about the same size as the bones of the ear, 

 and present nothing worthy of notice. 



The frontal bone has its surface concave, especially under the tem- 

 poral crests ; it forms an arch over the orbit, the thickest part of which 

 rests on the temporal bone, and the other on the jugal bone. 



Jugal bone very much arched, especially posteriorly, dilated ante- 

 riorly, on one side it rests on the angle of the temporal bone, and on 

 the other, on the zygomatic apophysis of the superior maxillary, and 

 on the lachrymal bone. The orbit is limited exteriorly by the fron- 

 tal and the jugal bones. 



The lachrymal bone is large and sub -triangular, but rather irregu- 

 lar ; it is very much depressed, and is placed on the extremity of the 

 zygomatic apophysis of the superior maxillary ; it occupies about a 

 quarter of the length of the suture, formed by the posterior edge of 

 this bone with the frontal bone. 



Temporal bone robust ; its superior apophysis slightly curved to 

 receive the apex of the jugal bone ; its crests very sharp and pro- 

 minent. 



Palatinal bones rather large and covering the extremity of the in- 

 ferior surface of the superior maxillaries ; they are prolonged as far 

 as the internal orifice of the blow-holes. 



The pterygoidal bones are narrow and look like little dog-tongues, 

 they are slightly curved upwards, their extremities being situated very 

 near the auditory apparatus. 



The bones of the ear are placed in the basilar region of the occipi- 

 tal bone, and look externally like two large, oviform, and convex tu- 

 bercles, which it is quite impossible to describe without figures. 



The central region between these bones is concave, and forms late- 

 rally on each side a small carena, which is directed on the bones of 

 the ear, and is distinctly notched anteriorly. 



The posterior sphenoidal bone is emarginated posteriorly in the 

 part which covers the basilar region. 



