44 ODOB^NUS EOSMARUS ATLANTIC WALRUS. 



ment of course greatly increase with age, and vary considerably 

 in resi)ect to direction, position, and relative development in 

 different individuals. The bony crests at the junction of the 

 intermaxillaries below the anterior nasal opening are especially 

 variable with age, becoming gradually obhterated in adult life 

 by the general thickening of the bones of the skull. They are 

 certainly less prominent in old age than in youth, and the same 

 is true of the incisive border of the intermaxillaries. The in- 

 termaxillaries, as a rule, only meet the nasals in their upward 

 extension, but in occasional sijecimens there is a narrow exten- 

 sion of them posteriorly between the nasals and maxillaries, 

 reaching for one-half to two-thirds the length of the nasals. 

 This variation is seen in the skulls figured by Goethe* and by 

 Blainville,t and has been noted in two skulls by Stannius.f In 

 other cases the intermaxillary rises to the surface between the 

 nasals and maxillaries only in the form of narrow isolated areas, 

 as is seen in a skull figured by Goethe, and in two skulls I have 

 myself examined. Hence Blain^aLle, when he says, " . . . . et 

 le pr6maxillaire, epais, remonte jusque entre le nasal et le 

 maxillaire, de maniere a circonscrire avec le premier I'orifice 

 nasal . . . . ,"|| describes the exceptional instead of the normal 

 condition. 



The nasals vary gTeatly in breadth and in length in different 

 specimens, and even in the same specimen one is sometimes 

 much wider than the other. The concavity and width of the 

 bony palate is also subject to much variation, in this respect 

 hardly two siDecimens being found to agree. In some, the con- 

 cavity is nearly one-fourth greater than in others. 



*Act. Acad. Cses. Leop. Carol., xi, pt. i, pi. iv, fig. 2. 



t Ost^ograpMe, Des Phoques, pi. i. 



t Says Stannius : "Bisweilen aber, wie bei den Kieler Scbadehi a tmd c, 

 tritt nocb eine diiime Leiste dieses Fortsatzes zwiscben die das Oberkiefer- 

 bein und das Nasenbein verbindende Langsnabt uud trennt eine Strecke weit 

 diese Ivnocben. So sieht man es aucb auf der in dem Blainville'scben "Werke 

 befindlicbcn Abbildung. Indem diese Leiste an einigen StelJen starker, an 

 anderu Stellen weniger stark oder gar nicbt nacb aussen bervortritt und zu 

 Tage kommt, bat es bisweilen den Anscbein, als fanden sieb isoliite Knocben- 

 stiickcben in der eben genannten Nabt. Wirklicb erwabnt de Fremery eines 

 zwiscben Nasenbein und Oberkieferbein vorkonunenden Ossiculum Wormi- 

 anum bei seinem aus Labrador stammenden "Walross-Scbiidel." Mullei''a 

 ArcMv fur Anat., 1842, p. 401. 



Act. Acad. Ca3s. Leop. Carol., Bd. xv, pt. i, 1831, pi. iv, fig. 1. 



11 Ost6ograpbie, Des Pboques, p. 20. 



