OF NORTH AMERICA. 353 



and 9) are excellent and answer exactly to Gould's description. These 

 are almost identical with the figures on plate XXXVII, which il- 

 lustrate the range of variation. Binney's figure of kirtlandiana bears 

 some resemblance to lanceata but quite correctly typifies kirtlandiana 

 in which the whorls are more oblique, a feature absent in lanceata. 

 Tryon's figure in his continuation of Haldeman's Monograph, is very 

 poor and looks more like a form of exilis than lanceata. (Hald. pi. 

 18, fig. 11). 



Lanceata is liable to be confused with three forms of Lymnaea; 

 exilis, which has a longer spire with more fiat-sided oblique whorls, 

 a narrower, more oblique aperture and a twist like that of reflexa; 

 immature reflexa, which differs in the form of the penultimate whorl 

 (which is disproportionately enlarged) and in the shape of the aperture, 

 which is slightly oblique and reflexed; and elodes, which has a wider 

 shell, wider spire whorls and a rounder aperture. With reasonable 

 care there ought to be no difficulty in distinguishing lanceata from all 

 related species. The spire whorls are only slightly oblique, notwith- 

 standing the fact that Gould says in his description "quite oblique." 

 The rectangular shape of the aperture and the flatly cylindrical form 

 of the body whorl, will aid much in distinguishing lanceata. 



Galba attenuata (Say). Plate XXXVII, figures 23, 24. 



Lymn&us attenuatus SAY, New Harm. Dis., II, p. 244, 1829 ; Binney's Ed., 

 p. 148; Discr., p. 23, 1858. 



Lymnaa attenuata JAY, Cat., Ed. 4, p. 268, 1852. 



Limnaus attenuatus KUSTER, Conch. Cab., p. 39, taf. 7, fig. 8, 1862. 

 Limnea attenuata HALD., Mon. Lim., p. 28, pi. 9, figs. 1-5, 1842. DEKAY, 

 Zool. N. Y., p. 75, 1843. 



Limncea attenuata BINNEY, Check List, p. 12, 1860; L. & F. W. Sh. N. A., 

 II, p. 42, fig. 53, 1865; Journ. de Conch., XV, p. 427, 1867. Sows., Conch. Icon., 

 Lim., XVIII, pi. 13, fig. 32 c, 1872. TRYON, Con. Hald. Mon., p. 95 (69), 1872. 

 STREBEL, Ab. Natur. Ver., Hamb., VI, p. 57, taf. 5, figs. 32, 32 a, 1873. PILSBRY, 

 Proc. Phil. Acad., 1891, p. 320. CR. & FISCH., Miss. Scient. Mex., Moll., I, taf. 

 27, figs. 11, 11, a, ib, II, p. 49, 1880. BAKER, Nat. in Mexico, p. 103, 1895. MAR- 

 TENS, Biol. Cent. Amer., Moll., p. 375, 1899. PILSBRY, Proc. Phil. Acad. 1903, 

 p. 776. 



Leptolimn&a attenuata TRYON, Amer. Journ. Conch., 1, p. 257, 1865. 



Omphiscola pugio BECK, Index Moll., p. 110, 1837 (sine descr.). 



Limnaa emarginata SOWB. (non Say), Reeve's Conch. Icon., XVIII, 

 Limnsea, pi. 6, fig. 35, 1872. 



Limnaus turritus PHILIPPI in coll. Dunker (vide Martens). 



Limnaus mexicanus ZIEGLER, in coll. Dunker (vide Martens). 



Limnaus subulatus DUNKER in Kuster, Conch. Cab., Ed. 2, p. 24, taf. 4, 

 fig. 24, 1862. VON MARTENS, Mai. Blatt, XII, p. 58, 1865. CLESSIN, MART. & 

 CHEMN., Conch. Cab., p. 395, taf. 16, figs. 1, 2, 1886. 



