60 PALUD1NID.E 



these mollusks inhabit deeper water than others of the 

 same family, such is not the case. They generally fre- 

 quent small streams^ canals, shallow ponds and ditches. 

 They lay their eggs in three long rows on stones, as well 

 as on the stalks and leaves of water-plants. 



1. ByTHINIA TENTACULATA^, Liuue. 



Helix tentacidata, Linn. Syst. Nat. ed. xii. p. 1249. BifJibvia teniaculaia. 

 F. & H. iii. p. 14, pi. Ixxi. f. 5, G, and (animal) pi. H. H. f. 3. 



Body dark brown or almost black above, dirty grey beneath, 

 covered with small and irregiUar specks of yellow : luad small 

 and semioval : snoid long and deeply cleft in front : tentacles 

 very long and slender, greatly diverging : eyes large, oval, and 

 black: foot much broader than the snout, rounded in front, 

 with a blunt and rounded tail which is half concealed by the 

 operculum when the animal is crawling. 



Shell subcorneal or oval, rather solid and glossy, nearly 

 opaque, of an amber colour, with often more or less of a brown- 

 ish tint, very finely and closely striate in a spiral direction and 

 crossed transversely by the marks of growth ; the spiral striaB 

 are sometimes confluent and form white hues : epidermis very 

 thin : whorls 6, convex ; the last exceeding one-half of the 

 shell, and the rest diminishing in proportion and ending in 

 rather a sharp point : suture rather oblique and deep : mouth 

 oval, angular above : outer lip thick, and sometimes strength- 

 ened by a white, rather strong, internal rib, which when re- 

 peated gives the shell a shghtly varicose appearance ; this hp 

 is very little reflected : inner Up united to the columella, but 

 forming with the other hp a complete peristome : umbilical 

 chink small and narrow : opercidum obhquely oval, very thick, 

 angadar at the top, compressed or indented in the middle of 

 the upper half; it is marked with exquisitely fine concentric 

 strige and a few coarser ridges, denoting the marks of periodical 

 increase, which form raised platforms or layers, the smallest 

 or first-formed being uppermost. L. 0-5. B. 0*25. 



Var. 1. ventricosa. Shell white : whorls more swollen. 

 Paludina ventricosa, Menke. 



Yar. 2. decollata. Ljoper ivhorls wanting in half-gro^vn and 



Having tentacles. 



i 



