486 LIMN^IDiE. 



as to give the appearance of a double suture. Tlie surfoce is ex- 

 ceedingly smooth, no revolving lines being detected by the magni- 

 fier. The base of the aperture is somewhat narrowed, and pro- 

 longed downwards, and considerably effuse. The twisted fold of 

 the columella is less conspicuous than in P. heterostropha. The 

 shell becomes more ponderous and yellowish by age ; and the red- 

 dish rib along the outer lip, and the enamel on the columella, much 

 thicker. 



Oeiius BULI]^US, Adanson. 1757. 



Tentacles filiform, setaceous. Mantle simple-edged, 

 and not reflcxed over the shell. Foot long, acuminate 

 behind. 



Shell sinistrorsal, elongated, polished, thin ; spire acu- 

 minated ; ai)erture narrow, produced anteriorly ; inner lip 

 simple ; outer lip acute. 



Jaw (of B. liijpnoruni) strongly arched, narrow, carti- 

 laginous, brown. 



Bulinus differs from PInjsa in having a simple, unfringed mantle. 

 The shell is also more slender and more highly polished. It is less 

 common in North America tban Ph/jsa, but usually appears of a 

 large size. Bulirms princeps, Phillips of Central America, and some 

 of the South American species, are remarkably well developed. 



Adanson's name Bulinus has priority over Aplexa, Fleming, and 

 Nauta, Leach, and is accompanied by a careful description and ex- 

 cellent figure. 



Bulinus elongatus. 



Fig. 143. 



Shell thin, slender, elong'ated, apex acute, pale yellowish ; whorls six, polished ; 

 snture slightly impressed ; aperture half as long as the shell. 



Pkijsa hi/pnontm, IIaldeman, Mon. -36, pi. 5, figs. 4-9 (1842). — Adams, Shells of Ver- 

 mont, 154 (1842). 



Physn elongata, Say, Jonrn. Acad. Nat. Sc. ii. 171 (1821) ; Binney's ed. 68. — Gould, 

 Inv. 214, fig. 143 (1841). -De Kay, N. Y. Moll. 81, pi. 6, fig. 346 (1843). — Anon. 

 Can. Nat. ii. 211, fig. (1857). 



Physa glabra, De Kay, N. Y. Moll. 80, pi. 5, fig. 83 (1843). 



Pltfisa elmgntina, Lewis, Best. Pr. v. 122, 298 (1855). 



Phf/sa turrila, J. de C. Sown. Fauna Bor.-Am. iii. 315. 



Apk'xa hiijmurnm, Cheni;, Man. de Conch, ii 481, fig. 3556. 



Bulinus hi/pnorum, W. G. Binney, Smith. Inst. L. and Fr. W. Sh. ii. 99, fig. 170 (1865). 



