CAPULUS. 



it is not recurved, nor is it in the least spiral. We are 

 fully aware that in full grown specimens of some of the 

 Capuli the beak is not recurved, but we observe that in 

 the young shells of the same species it is distinctly so. It 

 is somewhat singular that although the Capuli are gas- 

 teropods they do not appear to remove from the spot to 

 which they were at first attached, but like several of the 

 Patellae they seem to form, probably by a chemical action, 

 a more or less deep cavity in the surface to which they 

 adhere ; this circumstance alone, should, as we think, be 

 sufficient to distinguish the Capuli from the Hipponyces, 

 for it is evident that an animal with a mantle capable of 

 depositing testaceous matter, cannot at the same time 

 erode the spot to which it is affixing such calcareous 

 deposit. But there is a circumstance in the peculiar form 

 of the impression made by the foot of the Capulus which 

 it appears is difficult to understand, for the margin of this 

 impression is sometimes more or less raised in a somewhat 

 horse-shoe form, apparently corresponding to the muscular 

 impressions in the lower valve of Hipponyx : we think 

 this peculiar form may be caused by the contraction and 

 expansion of the nearly eircular foot in raising and de- 

 pressing the shell, in order to permit the entry and egress 

 of the sea water. 



Shell obliquely conical, recurved behind, with an 

 uncinate rather spiral apex ; aperture large, elliptical ; 

 muscular impressions two, lateral, joined together at 

 the back, each rounded in front. Epidermis horny, thick, 

 somewhat velvety. 



This Genus consists entirely of Marine shells, which 

 are frequently found adhering to oysters and other shells; 

 one species, namely, the C. Ungaricus abounds on our 

 coasts, and others are found in the Pacific and in the East 

 and West Indies. We are not acquainted with many 

 recent species. Several are common among the fossils 

 of the tertiary beds. 



We have represented in the upper figure a specimen 

 of Capulus Ungaricus as it commonly appears attached to 

 an oyster shell and in the lower figure the inside of the 

 same species. 



We are obliged to the Right Hon. Lady Elizabeth 

 Finch for living specimens brought from Tenby in January, 

 1832. 



