112 Proceedings of the Royal Society 
difference that I cannot regard them as identical. With the Green- 
land seal, again, the points of resemblance are, in some respects, 
very striking. They agree in the number, mode of arrangement, 
and relative size of the cusps, and in the mode in which the teeth 
are implanted in the jaws, though the teeth are set closer together 
in the fossil than in the Greenland species. Unfortunately, I have 
not had access to a young skull of the Pagopliilus groenlandicus , or 
to an adult clay seal, so that the materials for comparison have 
not, in this respect, been as perfect as to enable me to identify the 
species with accuracy. The examination, however, which I have 
made, leads me to think that these young clay seals maybe either 
immature specimens of the Pagophilus groenlandicus , or of a closely- 
allied species. But it will be difficult to express a positive opinion 
until adult skulls are compared with each other, and the skulls of the 
clay seals be compared with the crania of Pagomys foetidus, crania 
of which are not yet in my possession. 
Addendum, March Vlth . 
Since this paper was read to the Society, I have received some 
additional material of considerable importance in connection with 
the determination of the species of seal found in the glacial clay- 
beds of Scotland. Ur Howden has kindly sent me the bones of an 
adult seal, found in glacial marine clay at Puggiston, three miles 
from Montrose.* Through Mr William Livesay and Dr M k Bain, 
I have had the opportunity of examining three crania of the small 
arctic seal, Pagomys foetidus , Gray ( Phoca hispida , Cuvier). These 
skulls were from two adult and one young specimen. f 
The bones from Montrose included several vertebras and ribs, 
pelvis, scapulas, and the long bones of the extremities, together 
with the two halves of the lower jaw and the left upper jaw. They 
were found thirty feet below the surface, about three quarters of a 
mile from the tidal estuary of the South Esk, and about five feet 
* The geology of this district has been carefully described by Dr Howden 
in the Trans. Ed. Geolog. Soc. 1867-68. 
t These skulls were procured in the Spitzbergen seas during the arctic 
expedition conducted last summer by Mr Lamont. 
