TURBINATED UNIVALVES. 227 



l)rate animals, they form a section of the TracheUpods, which 

 he calls carnivorous. (Zoophages.) In the other section of 

 TracheUpods, which he calls herbivorous (Phytiphages) the 

 aperture of the shell is entire, and the animals have jaws 

 formed for feeding on vegetables. 



Mr. Diilwyn farther asserts, that every fossil Turbinated 

 Univalve of the older beds, from the Transition lime to the 

 Lias, belongs to the herbivorous genera ; and that the herbi- 

 vorous class extends through eveiy stratum in the entire se- 

 ries of geological formations, and still retains its place among 

 the inhabitants of our existing seas. On the other hand, the 

 shells of marine carnivorous Univalves are very abundant in 

 the Tertiary strata above the Chalk, but are extremely rare 

 in the Secondary strata, from the Chalk downwards to the 

 Inferior oolite ; beneath which no trace of them has yet 

 been found. 



Most collectors have seen upon the sea shore numbers of 

 dead shells, in which small circular holes have been bored 

 by the predaceous tribes, for the purpose of feeding upon 

 the bodies of the animals contained within them ; similar 

 holes occur in many fossil shells of the Tertiary strata, 

 wherein the shells of carnivorous Trachelipods also abound; 

 but perforations of this kind are extremely rare in the fossil 

 shells of any older formation. In the Green-sand and Oolite, 

 they have been noticed only in those few cases where they 

 are accompanied by the shells of equally rare carnivorous 

 MoUusks ; and in the Lias, and strata below it, there are 

 neither perforations, nor any shells having the notched mouth 

 peculiar to perforating carnivorous species. 



It should seem, from these facts, that in the economy of 

 submarine life, the great family of carnivorous Trachelipods, 

 performed the same necessary office during the Tertiary 

 period, which is alotted to them in the present ocean. We 



dicate their molluscous inhabitant to have been carnivorous, an entire aper- 

 ture does not always indicate a herbivorous character. 



