Researches in Fossil Zoology. 583 



stance can only happen when there is a giving way or erosion of 

 the cartilage, as by means of this structure the beaks are always 

 originally in connection. In lsocardia, for instance, we see 

 the beaks far separate, and the valves volute j* and it may 

 be seen that as the cartilage increases behind, it gives way 

 and becomes bifurcate before. The same spiral disposition 

 may be seen in the Chama, when the beak is nearly in the 

 centre of the valve ; and a still higher degree of remoteness 

 of the beaks is present in the fossil Diceras. 



We cannot account for the form of some shells without ad- 

 mitting that the animal has the power of lessening them at 

 certain points ; thus, in the Anomia the process of the under 

 valve to which the cartilage is attached remaining always in 

 the same place, and the notch being at all ages nearly a com- 

 plete foramen, how can this opening be enlarged for the in- 

 sertion of the increasing operculum,, without the possession 

 of such a power by the animal ? This effect appears to be 

 produced by currents of water directed against the edge of the 

 valve by the valvular organs of the animal. 

 (To he continued). 



Art. III. — Recent Researches in Fossil Zoology. By Hermann 

 Von Meyer. 



( Continued from page 553). 



In the grey chalk marl which underlies the yellow lime- 

 stone, near Neuf-Chatel, different vertebra [Wirbel] have 

 been found, and a large Saurus, which has been supposed to 

 be the Ichthyosaurus. Those vertebra which have a con- 

 cave surface belong neither to the Ichthyosaurus nor to the 

 Mososaurus :f the latter of which appears in the chalk for- 

 mation of the eastern and western world. My examination 

 of these is not yet finished. 



In my investigation and determination of the formation of 

 the environs of Neufchatel, it was of very important service 

 to me that the assembly of the Naturalists' Society of Switzer- 

 land gave me a crab to examine which was found in the yel- 

 low limestone, and which I recognized as the Ascotus longi- 

 manus of De la Beche, from the greensand near Lyme. It 

 is therefore no longer doubtful that the yellow limestone of 



* Sometimes, though rarely, the beaks of the two valves are volute in op- 

 posite directions, as in Inoceramus. 



f We must again remind our readers, that we received this article trans- 

 lated from the author's own German MSS. by Dr. Lenau. — Ed. 



