272 Mr. R. I. Pocock on some Dental and 
side; the general inflation of the shell is more evenly 
distributed throughout than is the case in LZ. rubrofusea, and 
the crenulation of the ventral margin is, in places, either 
obsolete or non-existent. 
Long. 3°25, lat. 4°25 mm. 
Hab. From the stomachs of fish taken in Bransfield Straits, 
South Shetland, in 15 fathoms (type) ; also washed from 
sea-weed dredged in the same locality and at the same depth 
(A. G. Bennett). 
Tellimya flavida, sp.n. (Fig. 8.) 
Shell rectangularly and obtusely cuneiform, covered with 
a yellow periostracum ; both valves concentrically striate ; 
umbones much eroded; dorsal margin slightly arched; 
ventsal margin very gently rounded ; anterior side abruptly 
descending, very slightly rounded; posterior side obtusely 
rounded ; right valve furnished with two broad grooves to 
receive the terminal portions of a slightly oblique, short, 
projecting, anterior and a more elongated, less oblique, poste- 
rior cardinal tooth in the left valve, these teeth being situated 
one on either side of the internal ligament. 
Long. 2, lat. 2°75 mm. 
Hab. From the stomachs of fish taken in Bransfield Straits, 
South Shetland Islands, at a depth of 15 fathoms (A. G. 
Bennett). 
EXPLANATION OF PLATE XIII. 
Fig. 1. Iimacina costulata, sp. u., X 6. 
Fig. 2. Lunatia bransfieldensis, sp. n., X 4. 
Fig. 3. Levilitorina claviformis, sp. n., X 8. 
Fig. 4. Pellilitorina bennetti, sp. n., x 10. 
Fig. 5. bransfieldensis, sp. N., X 4. 
Fig. 6. Iimatula deceptionensis, sp. n., X 6. 
Figs. 7, 7a. Lissarca bennetti, sp. n., X 6. 
Fig. 8. Tellimya flavida, sp. n., X 10. 
XXX.—Some Dental and Cranial Variations in the Scotch 
Wild Cat (Felis sylvestris). By R. I. Pococn, F.R.S. 
The Presence of Extra Premolars. 
In Felide the normal first upper premolar, pm? of the typical 
mammalian series, is very variable in occurrence. In some 
groups of related species it is practically constantly present ; 
SS = 
