92 



The grinders of the Proboscis Seal are only slightly plaited on the 

 crown, all have only simple subcylindrieal roots, which are cylindrical 

 in the young animal, and enlarged, short, and clavate in the adult 

 specimens. The grinders of the Crested Seal, on the contrary, are 

 rather tubercular and very closely and strongly plaited on the 

 crown, and this character is seldom obliterated by age, and in most 

 of the skulls the 4th and 5th grinder of both jaws have two roots, 

 and the root of the 3rd grmder is partially divided on the outer side ; 

 but in some adult skulls (probably belonging to the males ?) the roots 

 of the 4th and of the 1st, 2nd and 3rd grinders are enlarged and 

 simple-rooted, and in one young skull the 4th grinder is also simple- 

 rooted. 



I shall proceed to give the variations to be observed in the follow- 

 ing skulls, all received from Greenland : — 



1. No. 332 b. in Brit. Mus. Cat. — The skull of an adult or aged 

 specimen : the crowns plaited, the roots of all the grinders enlarged 

 and short, club-shaped and simple, separated from the crown by a 

 narrow collar. 



2. No. 332 a. — Skull of adult : the crown worn ; the root of the 1st, 

 2nd, 3rd, 4th, rather enlarged, oblong club-shaped, rather elongate, 

 the root of the 5th grinder compressed, of the left side simple, of the 

 right partially divided into two short roots continued in grooves on 

 each side. 



3. No. 332 c. — Skull of an aged specimen : the crowns plaited and 

 tubercular, the roots of the grinders rather enlarged, the root of the 

 3rd grinder rather compressed, simple, with a groove on the outer 

 side of the 4 th and 5 th grinders, scarcely enlarged, and divided into 

 two distinct diverging roots. 



4. No. 332 /*. — Skull of nearlj'^ adult : the crown of few grinders 

 remaining plaited ; the root of 4th and 5 th grinder of the left side, 

 as shown by the cavities, divided into two roots ; of the 4th grinder of 

 the right side simple, with a slight groove on the outer side, and of 

 the 5 th grinder two-rooted, like the similar grinder on the other 

 side. 



5. No. 332 d. — SkiUl of nearly adult, wanting the grinders ; but 

 the cavity for the grinders shows that the 4th grinder on both sides 

 had a short clavate root with a slight central groove on the outer 

 side, and the 5th grinder on each side had two separate roots. 



6. No. 332 e. — Skull of a half-grown animal: the crown plaited and 

 tubercular, the 4th grinder on each side with ovate, short, simple 

 roots, and the 5th grinder with compressed truncated simple roots ; 

 the grinders are rather further apart than in the other skull. 



7. No. 332/: — Skull of a very young animal : the crowns are very 

 distinctly plaited, the 4th and 5th grinders of both sides have two 

 distinct roots, and the 3rd grinder has a groove dovra the middle of 

 the outer side. In all these skidls the grinders are close together, 

 forming a nearly continuous line. 



8. Is the skull of a yomig female of the Seal caught in the Orwell 

 on the 29th of June, 1847, described and figured by Dr. W. B. 

 Clarke, and now in the Ipswich Museum. This skull very much 



