8 



The colour of the shell is brownish-green, with usually 

 several dark zones; it is sometimes, however, nearly 

 black. The umbones are tumid and obtuse, and paler 

 in colour than the other parts of the shell. The in- 

 terior is blueisb-white. The breadth of the shell is 

 ten-twelfths of an inch, its length eight-twelfths, and 

 its ventricoseness is little more than half-an-inch. 



The river cycle is rather abundant in the river Trent, 

 near Beeston Ryelands ; nevertheless it is difficult to 

 obtain in that locality. It is found also in the riier 

 Soar, near the Red-hill, at Thrumpton. Several speci- 

 mens have been procured from the canal, half a mile 

 below where it joins the Trent, at Beeston, yet they 

 appeared in an unhealthy condition. One dead speci- 

 rfien I dredged in a brook near the Nottingham and 

 Derby Railway, at Lenton ; in all probability this had 

 been deposited there in the time of a flood. 



Amongst the more distant localities, it grows to a 

 large size in the river Trent, near Barton (Brown) ; it 

 is found in great abundance in the river Thames 

 (Forbes), the New River (Bailev), the river Lea 

 (Hanley), the Yorkshire rivers (Winstanley), York- 

 shire streams (Bean), and the canals at Leamington 

 (Thompson). 



. Professor Forbes represents it as being found in 

 France, Germany, and Belgium, and, in a fossil state, 

 in the south of England, in the fresh- water beds of the 

 Pleistocene formation. 



