LIMNiEUS. 165 



forms as yet noticed, bear a striking resemblance to com- 

 mon existing types. These molliisks lay their eggs in- 

 vested in elliptical masses of gelatinous matter, enclosed 

 within a fine membranous envelope : these they attach to 

 stones or water-plants. The number of eggs in a single 

 bundle is often very great. 



" The character of the dentition of Limnaus,'''' observes 

 Mr. W. Thomson, " appears to be, to have one small 

 central tubercle, as it were squeezed up between two very 

 large lateral ones, each primary lateral having a very large 

 apex internally, with a small external one, quite at the 

 edge ; they have altered to one thick prolonged apex pro- 

 jecting inwards, and irregularly lobed on its upper edge. 

 Much the same arrangement prevails in AmphijJejplea, where, 

 however, the tubercle of the lateral teeth is even still 

 larger in proportion to its plate." 



The genus Amphipeplea was constituted by Nilson for 

 Lbnnaus cflutinosus on account of its large mantle lobes, 

 which the animal reflects over the shell when crawling. 

 \Ve have regarded it as a section of Limnceus* 



L. PEREGER, Miiller. 



Striolate ; body abruptly larger; spire short; its whorls not 

 abruptly severed, but convex or rounded ; outer lip slanting at 

 its junction with the body-whorl; columellar lip not strongly 

 contorted, nor bent to the left, curved below. 



Plate CXXIII. fig. 3 to 7. 



List. Aniin. Angl. pi. 2, f. 23. — Schrot. Fllissc. pi. G, f. 8. 

 Buccliiain perer^rum, MiJLLER, Verm. Hist. vol. ii. p. 1 30. 



* The Llmttcus detritus, of Turton's Manual (p. 125) was described from a 

 young specimen of the Bulimus Zebra ! of Muller (Pfeif. Monog. Helic. vol. ii. 

 p. 143; the imJatus of Bruguiere). The types of the Helix detritus of Pultency 

 and Montaj^u, both prove to be a white variety of the West Indian D. cjciiis 

 (Pfeif. Monog. Ilelic. vol. ii. p. 224). 



