226 THE SKULL. [CHAP. 



the ascending processes of the premaxillae below, and by 

 the supraorbital processes of the frontals above, no trace of 

 nasals being found in most skulls, though these bones are 

 occasionally present in a most rudimentary condition attached 

 to the edge of the frontals, far away from the middle line, 

 a condition quite unique among the Mammalia, or only 

 approached in some of the Dolphins. In the floor of the 

 great narial opening is seen the vomer ( Vo), of very delicate 

 structure, and posteriorly the ossified portion of the mes- 

 ethmoid (ME) of considerable vertical extent. The olfac- 

 tory chamber of the nasal cavity is greatly compressed from 

 side to side, and contains a series of simple, longitudinally 

 placed ethmoturbinals, of which the upper one is very much 

 the largest. There are no maxilloturbinals in any skulls 

 which I have examined. 



In front of the narial opening the face is prolonged into 

 a narrow rostrum, formed by the premaxillse, supported 

 below and at the sides by the maxillae. The under surface 

 of this is very rugose, and in life supports a horny plate. 

 There is a large, oval, single, median anterior palatine 

 foramen. The palate is long and narrow between the two 

 parallel rows of numerous molar teeth. It does not extend 

 beyond the last of these, and is formed almost entirely by 

 the maxillae, the horizontal plates of the palate bones 

 being very narrow. Behind each row of teeth is a massive 

 descending rough process, formed by the union of the 

 palatine, pterygoid plate of the alisphenoid, and true 

 pterygoid. Posteriorly this has a longitudinal groove cor- 

 responding to the pterygoid fossa. Behind this the base 

 of the skull contracts in width, leaving a large opening on 

 each side of the basioccipital, between the alisphenoid in 

 front and the exoccipital behind, and only partially filled by 

 the tympanic and periotic. 



