Reptiles. 9559 



also; and now, liaving obtained some perfect and living specimens, I find tbat I was 

 right in iny cdnjecture. The largest I bave as yet obtained is 6i incbes long, 

 I incb wide at the hinc;e, and If inch when measured at the distance of H inch iVoin 

 the binge-end or beak, while the broadest part is 3| inches in width. Tiie greatest 

 external height of the shell is If inch. The balf-deck-like and grooved binge (the 

 very distinctive peculiarity of this oyster) is of the usual triangular form, with a deep 

 undulation in the centre, and measures three quarters of an incb in length ; that is, 

 from the back, or point, of the triangle, to the front, and Ig of an inch at the broadest 

 part, or base, of the triangle. To avoid any damage to the shell by opening it with a 

 knife, 1 preferred boiling it, and was therelore nnable to draw or measure the animal 

 in its living slate; but even though shrunk up by the hot water, it presented a veiy 

 different appearance from our well-known round Ostrea edulis when similarly treated, 

 being oblong and straight-sided, and measuring 2^ inches in length by I5 inch in 

 breadth. The individual which I have described appears to be a young one; for in 

 the full-grown Ostrea virginica of Spain the beak (and with it the binge) frequently 

 becomes depressed or bent downwards. I have, however, found the depressed end in 

 other smaller specimens at Tenby, one of which, though very small (only 2 inches long 

 by fths of an inch in breadth), presents the most marked peculiarity of the 0. vir- 

 ginica in its long narrow trough-like conformation, scarcely varying in width throughout 

 its length. But here, as in Andalusia, the outline of the shell is very variable in 

 different specimens, — a remark which applies to the whole family of oysters. The 

 septum, or half-deck, which supports the hinge-plate is, moreover, a constant and un- 

 mistakeable feature by which to recognize the 0. virginica, independent of its other 

 peculiarities. I have also found at Tenby a very small specimen, little more than 

 1 inch in length by fibs of an inch in breadth, which has every appearance of being a 

 young shell, but which has the " half-deck" with a deep hollow space receding beneath 

 it, and this is prolonged into a tail-like projection, or spur, ctirving downwards to a 

 length of fths of an incb, and terminating in a sharp point. The depth of the shell 

 itself is ^th of an inch. I have not attempted at this season of the year to dredge, so 

 that I have only been able at present to obtain these shells occasionally at low water; 

 but that the 0. virginica prefers, in England as in warmer latitudes, the mouth of a 

 river, is shown by the greatest number of specimens being met with in the neighbour- 

 hood of the small stream which runs into the sea on the south sands of Tenby. But, 

 as we might naturally expect, the fish cannot exist, in this cold climate, in a shallow 

 and exposed situation ; they are not, therefore, found in the stream itself, as they are 

 at the month of the Guadalete, where, though every tide on receding from its muddy 

 banks leaves the oysters more or less exposed, they are not affected by the change. 

 Here, at Tenby, even within the influence of the warm current which softens the 

 climate of this coast, they can only exist in a certain depth of water, though probably 

 at no very great depth ; but this and other points I can only hope to decide by 

 dredging. — Gardner Wilkinson; South Cliff House, Tenby, March 31, 1865. 



Note on Coronella lavis. — In Dr. E. Opel's most interesting and valuable account 

 of the habits of the smooth snake (Zool. 9505), he does not mention the fact that it 

 has the power of " stinking se defendo " (as White of Selbourue says of the common 

 species). A specimen which I took in August, 1862, in the Valley of the Neckar, 



