HIPPONYX. 



fossil shells from near Paris, which confirmed us in our 

 opinion, and established the Genus. If any further evi- 

 dence of the bivalve nature of the Hipponyx were neces- 

 sary, it is abundantly supplied by a recent discovery of our 

 esteemed and liberal friend C. De Gerville's, who had 

 already enriched M. De France's and our own collections, 

 with many specimens of the detached valves. In the latter 

 part of the Summer of 1821, he met with several fine 

 specimens with both valves together, and attached to Ceri- 

 •thium Cornucopia, at Hauteville, in the Department de la 

 Manche; some of these he has obligingly forwarded to us; 

 and had not our plate been already in the printer's hands, 

 we should have availed ourselves of this opportunity, and 

 have given a representation of one of them: if circum- 

 stances should hereafter render it necessary we shall give q, 

 new plate. 



The only recent species that is certainly known to 

 belong to the Genus Hipponyx, is the Patella mitrata of 

 Linnc, of which the attached valve is in M. De France's 

 collection. The upper valves of several fossil species have* 

 been described by Lamarck, among his fossil PatellcE^ under 

 the specific names Cornucopia and dilatata ; most of them 

 are covered with striae diverging from the umbo or zertex., 

 and spreading to the edges all around ; one is covered with 

 strong costas, diverging in a similar manner, and another 

 is smooth. All the fossil species known are from the Col- 

 caire grossiere of the French, which, we think, is nearly, if 

 not quite, identical with our London clay; though we are 

 not aware of a single one having yet been found in England. 



We cannot conclude this article without recommending 

 to those, who have opportunities of collecting shells in a living 

 state, to pay an increased attention to their nature and eco- 

 nomy. It appears to us a strong proof of the general careless- 

 ness and inattention of collectors, that the true nature of so 

 common a shell as Patella mitrata should so long have 

 remained unknown, and that it should be, at length, dis- 

 covered, not in the places where it is found abundantly, 

 and where, consequently, the best opportunities were 

 afforded, but by a person shut up in his study, at a distance 

 from the sea-coast, and deprived of the means of observing 

 it in its living state. There is reason to believe that several 

 other recent species exist, but that only their upper valves 



