Zoological Society. 59 



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 4th and 5th grinders, scarcely enlarged, and divided into 

 two distinct diverging roots. 



4. No. 332 h. — Skull of nearly adult : the crown of few grmders 

 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 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 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 

 resembles No. 6 (No. 332 e.) in proportions and distance of grinders, 

 but is only about two-thirds the size, and the blood-vessel on each 

 side the palate, which in that skull is open, is here partly covered 

 over with a thin layer of bone ; the 4th upper grinder has a com- 

 pressed simple root with a groove on the lower part of its outer side, 

 and the 5th grinder is two-rooted. It is to be observed, that the 

 Orwell specimen. No. 8, was a female, and that the nose of this and 

 of skull No. 6 diifer from the others in being rather longer, and in 

 the grinders being rather further apart : is this the character of the 

 female sex ? and in both these skulls the 4th grinder is single-rooted: 

 is that also a sexual character 1 It is to be hoped that the Danish 

 or American naturalists who have the opportunity of examining these 

 seals, will determine the question. 



It would thus appear, from what I have stated, that in this genus 

 the form of the root of the grinders is very liable to variation ; I 

 have not observed any similar variation in the teeth of any other seal, 

 and still believe that the form of the roots affords a good character 

 in most of the genera. 



We have lately received from the West Indies the skin and skull 

 of a seal which evidently belongs to the same genus as the crested 

 seal of the northern hemisphere. The skull, or rather the teeth. 



