INVERTEBRATE PALAEONTOLOGY. 603 



PHYSID/E. 



Genus PHYSA, DraparnautL 



SijiioH.—riiysa, Draparn. (1801), Proilr. : and (1805) Moll., 25, 28, and 54.— Lam. (1812), Extr. d'un Cours ; 

 and (1822) Hist., VI, 2, 155 (2e eU, 398).— Fe"russ. (1821), Tabl. Syst., xxxiii.— 

 Blainv. (1824), Diet. Sci. Nat., XXXII, 244; and (1825) Malac, 450.— Defr. (1826), 

 Diet. Sci. Nat., XL, 145.— Fitzinger (1833), Syst. Verz., 110.— Cbarp. (1837), Cat. Moll. 

 Suisse, 29.— Gray (1840), in Turt. Man. (2d ed.), 251; and (1842) Synon. Moll. Brit. 

 Mas., 91; also (1844) Eev. Zool., 405.— Haldeman (1842), Mon. Fresh-water Univ. 

 United States, Physidw, 20.— Swainson (1840), Malac, 338.— Gould (1841), Invert. 

 Mass., 211 ; and Binney ed. same (1870), 483. — H. and A. Adams (1855), Genera Recent 

 Moll., II, 256. — Binney (18G5), Land and Fresh-water Shells United States, 75; and of 

 many others. 



Phyza, Eisso (1826), Hist., IV, 96.— Verany (1846), Cat. An. Invert., 15. 



Anissus (part), Studer (1820), Syst. Verzch., 23 (not of Fitzinger). 



Isidora, Ehrenb. (1831), Symb. Phys.— H. and A. Adams (1855), Genera Recent Moll., II, 260 (as a 

 subgenus under Bittinus). 



Kivkola, Fitzinger (1833), Syst. Verz., 110. 



Physellu, Haldeman (1842), Monogr. Fresh-water Univalves of the United States, 14 (proposed 

 as a subgenus under Physa). — H. and A. Adams (1855), Genera Eecent Moll., II, 25 (as 

 a subgenus under Physa). 



Physodon, Haldeman (1842). Mon. Fresh-water Univalves United States, 14 (proposed as a sub- 

 genus under Physa). — H. and A. Adams (1855), Genera Recent Moll., II, 258. 



Costella, Dall (1870), Ann. Mag. N. Y. Lye. Nat. Hist., IX, 355 (as a subgenus under Physa). 



Etym. — ipvaa, a leather bag, or bellows. 

 Exam]). — Physa fontinalis, Linn. (sp.). 



Shell ovate, elliptic, or subglobose, thin and polished, or moderately 

 thick; spire short ; aperture subovate, or more or less elongated; outer lip 

 thin, or rather thick, and not dilated; inner lip spread over the columella, 

 which has a more or less developed fold, or slight tooth-like projection. 



As defined above, this genus includes, along with the typical forms, four 

 other subgenera, among recent species; and probably-otbers will have to be 

 established for some extinct forms. The separate subgenera alluded to were 

 established by Professors Haldeman and Ehrenberg and by Mr. Dall, and 

 may be distinguished from each other and the typical section as stated below : 



1. physa, Draparnaud (typical). 



Shell subovate or subelliptic; outer lip thin ; columella with fold 

 small or nearly obsolete. — (Type as already stated.) 



2. physella, Haldeman. 



Shell subglobose; spire very short; aperture comparatively 

 large; columella with a well-defined fold. — (P. globosa, Haldeman.) 



3. physodon, Haldeman. 



Shell comparatively thick, smooth, subovate ; columella with two 

 tooth-like projections; outer lip thick. — (P . microstoma, Haldeman.) 



