PLANORBIS. 43 



8. P. carina'tus,* Muller. Pl. IV. 



Body dark reddish-brown, slightly greyish beneath, indistinctly 

 spotted with black; tentacles slender but somewhat thickened 

 at their base, transparent, yellowish, with a tinge of pink, tips 

 bluntish ; eyes very [small, round, black ; foot reddish-grey 

 beneath, darker towards the middle, roundish in front, and 

 ending in a broadish, blunt tail. 



Shell compressed, concave above, nearly flat or slightly convex 

 beneath, thin, somewhat glossy, slightly transparent, pale 

 brownish horn-colour, with fine close-set striae in the line of 

 growth, and faintly striate spirally ; epidermis thin ; periphery 

 prominently keeled in or near to the centre ; whorls 5-6, rather 

 rapidly increasing in size, body whorl sloping gradually towards 

 the periphery on both sides ; suture deep ; mouth obliquely oval, 

 acutely angulated above, sometimes furnished with an internal 

 rib ; outer lip very little reflected ; iither lip widely spread over 

 the base of the penultimate whorl and continuous with the other; 

 umbilicus very small. 



Inhabits slow rivers and stagnant water in many- 

 parts of Great Britain, but it is local and not very- 

 abundant where it does occur. It seems to be most 

 plentiful in the home and eastern counties, but its 

 range is somewhat wide, as it has also been found 

 in those of Dorset, Somerset, Northampton, York, 

 Durham (W. D. Sutton), Oxford (D. Pidgeon), as 

 well as in some parts of Wales and Ireland. 



It is an inactive species, at one time attaching 

 itself firmly to smooth substances, at another floating 

 idly on the under surface of the water. 



Its eggs, to the number of ten to twelve, are laid 

 during the months of May, June, and July, and are 

 deposited in roundish capsules, the fry being hatched 

 in about ten or twelve days. 



Keeled. 



