Potamopyrgus.} GASTROPODA. 233 



Subsp. Salleana, P. Fischer, 1860. Plate 14, fig. 4. 



Paludestrina Salleana, Fisch., J. de Conch., viii, 1860, 208, 209, pi. 4, f. 6. 

 Potamopyrgus corolla, Gld., subsp. Salleana, Fisch.: Suter, T.N.Z.I., 

 xxxvii, 247, 262. 



Shell horn-colour, conical, thin. The last 4 whorls are spinous ; 

 the spines are short, black, directed upwards ; typically there is a 

 chordate carina on the last whorl below the row of spines. Whorls 

 7-7|, flatly convex. Aperture ovate. Peristome continuous, but little 

 callous. 



Diameter, 3-5 mm. ; height 6 mm. Ratio of D : H == 1 : 1-7. 



This subspecies differs from corolla in being more slender, less 

 ventricose, in having spines on the last 4 whorls (against 3 in the species), 

 and a chordate carina below the row of spines, which, however, is 

 quite an exceptional occurrence ; very often specimens are subangled 

 below the periphery. 



Type. Collection of the " Journal de Conchyliologie," Paris. 



Hab. Widely distributed throughout the North Island ; Pelorus 

 River, Nelson, and Collingwood, South Island. 



Remarks. All the specimens in my collection are yellowish-brown, 

 thinner than corolla, mostly without spines, and some are larger than 

 the type : diameter, 4-5 mm. ; height, 8 mm. The Nelson specimens 

 are from brackish water. The only specimens with a slight chordate 

 carina below the series of spines are from Lake Manapouri. 



4. Potamopyrgus egenus, Gould, 1848. Plate 14, fig. 5. 



Amnicola egena, Gld., P. Bost. S.N.H., iii. 1848, 75. .4. gracilis, Gould, 

 U.S. Expl. Ex., xii, 127, f. 151, a, b. Bythinella egena, Gld. : Hutton, 

 M.N.Z.M., 82 ; T.N.Z.I., xiv, pi. 1. f. 0, upper right figure. Potamo- 

 pyrgus egenus, Gld. : Suter, T.N.Z.I., xxxvii, 265. 



Shell elongate, minute, turreted, delicate, smooth, with faint striae 

 of growth. Epidermis thin, pale green. Spire acute, much higher 

 than the aperture. Protoconch minute, globose. Whorls 5 to 7, regu- 

 larly increasing, convex, the last one half the length of the shell ; 

 base rounded. Suture impressed. Aperture ovate, one-third the 

 length of the shell, angled above. Peristome continuous, acute, white 

 and slightly callous inside ; there is an indistinct umbilical chink or 

 the inner lip is separated from the body by a narrow groove. Oper- 

 culum typical. No carinated or spinous forms are known. 



Diameter, 2-5 mm. ; height, 5 mm. (type). Diameter, 2-25 mm. ; 

 height, 5 mm. (specimen with 7 whorls). Diameter, 1-75 mm. ; height, 

 4 mm. (specimen with 6 whorls). 



Animal unknown. 



Type in the U.S. Nat. Museum, Washington. 



Hab. Banks Peninsula (type) ; Little River, Banks Peninsula 

 (H. S.) ; Nelson ; Kaiwarrawarra River (H. S.). 



Remark. The species is rare and local, but well marked by its 

 graceful elongated form. 



