RISSOA. 145 



species (pi. LXXXVII. f. 8), is smaller and shorter than 

 the typical form, is of a clearer fulvous hue, and displays 

 rather more convexity in the whorls, basal declination, and 

 general outline. The mouth is longer and narrower ; its 

 posterior contraction is consequently more acute and gra- 

 dual. The outer lip is but little prominent, and the reflec- 

 tion of the inner one is narrower than usual. Professor 

 Bronn, of Heidelberg, sent us similar shells as the Paludina 

 stagnalis of Menke (Zeitsch. Malakozool. 1845, p. 37), 

 stating that they had been forwarded to him from Nor- 

 derney through that author. 



AVe have regarded the B. Barleei (pi. LXXXI. f. 8, 9) 

 as only a deep-water form of this most variable species, 

 since the peculiar characteristics which distinguish the 

 more strongly marked examples are not present in all the 

 individuals taken on the same spot, but merge perceptibly, 

 in certain of them, into the ordinary features of ulv^ proper. 

 The more singular specimens are decidedly more cylindra- 

 ceous than in the typical or shore variety, have the apex 

 usually eroded, and display a remarkable contraction in 

 the size of the aperture, not so much as to the relative 

 proportions of height between it and the spire (the latter, 

 however, is occasionally thrice as long as the former) 

 as in the very small proportion of the entire area of the 

 shell that is occupied by it. We received a similar shell 

 from Professor Loven, of Stockholm, as the Paludina 

 Balthica of Nilsson (Moll. Suecia3, p. 91). A small variety 

 is taken in Torbay, which is narrower than usual, and has 

 for the most part only a third of the ventral length occu- 

 pied by the movith ; the apex is occasionally rufous. We 

 have likewise taken in the Channel Islands (S. H.) a 

 few specimens that were almost cylindrical in the middle, 

 the penult and antepenult turns being of nearly the same 



