FOSSIL FRESHWATER SHELLS. 1 1 1 



The Limneus,* (PL I. figs. 3, 4, 5,) is characterised 

 by its elongated oval form, pointed spire, and deli- 

 cate shell, with an oblique fold on the inner lip 

 of the aperture ; of this genus there are six species 

 in the tertiary strata of the Island. The Bulimus,\ 

 a genus of land snails, is comparatively rare at 

 Binstead; but casts of the large species figured 

 PI. I. fig. 7, are occasionally met with, invested with 

 a white friable coating of the original shell. This 

 species is a reversed shell, that is, the aperture is 

 to the left of the observer, instead of to the rierht. 

 as is most common ; some specimens are two inches 

 in length. There are indications of a sjjecies of 

 Cyclas,% a genus of freshwater bivalves, but the 

 examples met with are not sufficiently perfect to 

 require particular notice. A small species of 

 Unio$ is also sometimes found. 



Specimens of the Cypris,\\ a small freshwater 

 crustacean, of which several species abound in 



* Limnei and Planorbes are generally joint inhabitants of our pools and 

 streams. They are pulmoniferous, that is, possess air-breathing organs ; 

 hence they are obliged frequently to rise to the surface of the water to respire. 



t Bulimus (properly hulinus), a genus of terrestrial pulmoniferous testa- 

 ceous mollusca. These animals are herbivorous, and some of the species that 

 inhabit warm climates are very large, their eggs being equal in size to those 

 of the Wren. 



X Medals of Creation, p. 411. 



§ Unio, a genus of river mussels, of which a few fossil species have been 

 observed in certain deposits apparently of (luviatile or lacustrine origin. 



|| Medals of Creation, p. 544. 



