FAMILY PERISTOMATA. 199 



Nerita obtusa, Studer (1789), Coxe, Trav. in Switz. vol. iii. p. 436. 



Turbo fontinalis, Pulteney (1799), Cat. Shells, Dorset, p. 45. 



Turbo eristatus, Poiret (1801), Coq. de VAisne, p. 29 (not of Maton and 



Rackett) . 

 Cyclostoma obtusion, Draparnaxid (1801), Tabl. Moll. p. 39. 

 Valvata minuta, Draparnaud (1805), Hist. Moll. p. 42. pi. i. f. 36 to 38. 

 Valvata piscinalis, Ferussac (1807), Ess. Syst. Conch, p. 75. 

 Lymncea fontinalis, Fleming (1814), Edin. Eneyc. vol. vii. p. 78. 

 Valvata obtusa, Brard (1815), Coq. Paris, p. 190. pi. vi. f. 17. 

 Turbo thermalis, Dillwyn (1817), Bese. Cat. Shells, p. 852. 

 Valvata depressa, C. Pfeiffer (1821), Deuts. Moll. vol. i. p. 100. pi. iv. f. 33. 

 Valvata Moquiniana, Reynies (1851), Dupuy, Hist. Moll. vol. v. p. 586. 



pi. xxviii. f. 15. 

 Hab. Throughout Europe. Siberia. Asia Minor. (Adhering to stones, 



submerged sticks, etc., in tranquil and gently running waters.) 



Valvata piscinalis is almost milk-white, showing its bright blue- 

 black eyes very conspicuously on the inner base of each tentacle. 

 The shell is of a gradually enlarging turbinated growth, of a pale 

 semitransparent straw-colour, faintly spirally ridged. Sometimes 

 the ridges are very apparent, sometimes they are almost obsolete, 

 and the whorls of the shell being more or less closely convoluted, it 

 follows that the umbilicus is more or less open. There is much 

 reason to believe that more of the species of Continental authors 

 have been founded on these variations of growth, than appear in 

 our list of the synonymy. V. piscinalis is very generally diffused 

 throughout Europe and Western Asia. The most northern habitat 

 is that recorded by G-erstfeldt in Siberia ; the most southern that of 

 specimens in my possession, collected by Captain Spratt, in Lycia. 

 The species is found in all parts of the British Isles, and it is very 

 closely represented in the West Indies by V. depressa. 



M. Moquin-Tandon describes V. piscinalis as being slow in its 

 movements, and very irritable, sometimes crawHng on solid bodies, 

 sometimes swimming on the surface of the water, moving itself in 

 all directions by the two crescent segments in the front part of the 

 foot, and continually agitating its protruded trunk, while it falls on 

 the least touch to the bottom of the water. Mr. Jeffreys notices that 

 the eggs of this mollusk are deposited on various substances, some- 

 times on the shell of a Planorbis, enclosed in a globular capsule, 

 having a short stalk by which it is attached. About the twelfth 

 day, the capsule distends and bursts, and the young fry are ejected 

 aHve. 



