78 LAND AND FRESH-WATER SHELLS OF N. A. [PART IIL 



Leptoxis isognna, Haldemax, Mon. 6, pi. v, f. 155 {Mudalia) (1847?). 

 Paludina sub;jlohosa, Say, J. A. N. Sc. V, 125 (1825) ; Binney's t-d. p. 



115.— DeKay, N. Y. Moll. p. 86 (1843).— Haldeman, Mon. pi. x, f. 



7,8. 

 Mr. Lea's description and figure of Paludina j^allida are 

 copied below. 



Paludina pallida. — Shell ventricose, thin, light horn-color, smooth; 

 sutures impressed ; whirls four, convex ; aperture nearly round. 



Ifear Cincinnati, Ohio : T. G. Lea. My cabinet. Diam. .3 

 Fig. 153. length .4 inch. 



This shell has recently been found by my brother, and I 

 believe has not before been observed. It might at first be 

 mistaken for a young shell, on account of its pale yellow 

 color and translucency. In form, however, it differs from any 

 species I have examined, the last whirl being very much en- 

 larged, and the aperture being very large. (Lea.) 



A translation of Philippi's description of Paludina fovtiiialis, 

 and a fac-simile of his figure here follow. The shell described 

 by him may be S. integer. 



Fig. 154. Paludina fontinalis. — Shell minute, subglobose, sub- 



perforate, solid, greenish-yellow ; whirls four, convex, 

 the last ventricose, twice the length of the shell ; aper- 

 ture ovate, dilated. Height 21'" (lines), diameter 

 2^'" ; height of the aperture If'". 



Melanin integra, Say (ubi?), according to specimens. 



Ohio, United States of America. {Philippi.) 

 Paludina fontinalis. 



An authentic specimen of Paludina suhglohosa, preserved in 

 the Philadelphia Academy, is without doubt identical with the 

 shell received as Say's Melania isogona. A drawing of the 

 specimen and copy of Say's description here follow. 



The strict rules of nomenclature would require the substitution 

 of subglobosus for isogonus as the specific name of this species. 

 It does not, however, seem advisable in this case to abandon the 

 name by which the species has so long been known. 



Fig. 155. Paludina suhglohosa, Say. — Shell subglobose ; whirls three 



and a half, much rounded, rapidly enlarging ; suture pro- 

 foundly impressed ; aperture suhovate ; umbilicus very nar- 

 row, nearly closed by the labrum ; spire very short, convex. 



„ J ^^^f^ Inhabits the Northwestern Territory. Length less than three- 



glohosa. tenths of an inch. 



