227 



three holes in the lower valve as sufficient to demand for them a distinct 

 genus. Bruguiere has made out four species, three of which are fossil. 

 Being unacquainted with these fossils, I have, for their illustration, copied 

 the representation of the lower valve of C. per sonata, Lain. -Anomia cranio- 

 laris, Linn. Plate XVI. Fig. 3, from Plate vn. of Hist. Nat. des Coquilles, 

 par Bosc. 



CLII. Terebratula. A regular shell, fixed by a cartilage or short 

 tube, and composed of two unequal valves, the largest of which has its 

 beak produced and pierced with a hole, through which the cartilage 

 passes. The hinge with two teeth. 



After having abstracted from the Linnsean genus Anomia, the shells 

 forming the genera Anomia, Crania, Calceola, and Hyal&a, it was intended, 

 by Lamarck, to place under the present genus Terebratula, the remainder 

 of those shells which had been hitherto considered as Anomiae. But con- 

 siderable difficulty will be still found to exist, as to the classification of 

 these shells. Mr. Martin, whose accuracy and judgment, displayed in 

 the division of the shells of this genus, might alone suffice to render his 

 work highly valuable, and to make every lover of science regret his loss, 

 has shown that, among these shells, there exist much greater differences 

 than Larharck is apprized of! He found it necessary, on this account, 

 to arrange them in the four following families: 1. Irnperforated, with 

 one valve flat, and with a straight, extended, and narrow hinge. 2. Per- 

 forated, both valves convex ; the hinge straight and patulous, with a 

 large trigonal foramen between the beaks: these are subdivided into 

 those with a long or a short hinge. 3. Perforated, both valves convex ; 

 the beak of the larger valve incumbent, with a very small trigonal or 

 oblong foramen : the hinge close and curved. 4. Perforated, both valves 

 convex, the beak of the larger valve pierced by a tubular opening; the 

 hinge close and curved. 



It is evident, that, of these four families, the shells of the two last only 

 can be placed, in strictness, under this genus the imperforated, and 

 those with a large trigonal foramen between the beaks, cannot be made 

 to correspond with the description of the genus Terebratula. The consi- 



