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92 
The grinders of the Proboscis Seal are only slightly plaited on the 
crown, all have only simple subcylindrical 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 grinder 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 Ist, 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 4. 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 Ist, 
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 ¢.—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 4th and Sth grinders, scarcely enlarged, and divided into 
two distinct diverging roots. 
4. No. 332 h.—Skull of nearly adult: the crown of few grinders 
remaining plaited ; the root of 4th and 5th 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 5th grinder two-rooted, like the similar grinder on the other 
side. 
5. No. 332 d.—Skull 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 ofa 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 f.—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 down the middle of 
the outer side. In all these skulls the grinders are close together, 
forming a nearly continuous line. 
8. Is the skull of a young 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 
