172 ruocicuDiNGs of tiik jialacological society. 



Pi-KUROCEKA liiT^NiATA (Conrad). 

 2[eJania hifaniata, Conntd, 1834; 77/". curta, Haldeman, 1841; 21. 

 jDumilia, Lea, 1845; II. solida, Lea, 1845 (preocc); If. corpulenta, 

 Anthony, 1854; Streptohasis Spilhnanii, Lea, 1861; S. cornea, 

 Lea, 1861; S. Clarkii, Lea, 1861; S. ollvaria, Lea, 1862; 

 S. carinata, Lea, 1862; S. Lyonii, Lea, 1864. 

 Shell of moderate size, conic-subpupiforra, wliorls appressed, com- 

 pressed, and somewhat concave above the sub-iounded peripherv, 

 aperture sub-elliptical, narrowing above, columella callused, outer lip 

 sinuate and cluinnelled at base; habitat streams. 

 Tennessee and Alabama Itivers, American Province. 



Pleurocera solida (Lea). 

 Anculosa solida. Lea, 1842; Melania brevis. Lea, 1842; Lithasin 

 Showaltherii, Lea, 1850 ; II. compacta, Anthony, 1857 ; L. nuclca, 

 Lea, 1860; If. trivittata, lleeve, 1860; L. fusifonnis, Lea, 1861 ; 

 L. vittata, Lea, 1862; L. Doicniei, Lea, 1862. 



Sliell similar to preceding but more slender-conic, wliorls appressed 

 and slightly shouldered at periphery, aperture narrowly elliptical and 

 produced above and below, columella not heavily callused, outer lip 

 but slightly sinuate and not prominently channelled at base; habitat 

 streams. 



Coosa and ? Cumberland Rivers, Alabama, American Province. 



Tryon has written solida as a synonym of brevis, described bv 

 Lea on a preceding page of the same article. He says, however : 

 "Mr. lleeve has not recognized the genus Lithasia, and accordingly 

 changes the name (i.e. brevis) to trivittata, Reeve, because Mr. Lea had 

 already used brevis for a Melanian." Reeve's monograph has not 

 been at hand to verify Tryon's statement, and there is no record in 

 Scudder's Index that Lea described more than the one Melania brevis. 

 Owing, however, to the enormous number of specific names used 

 under Melania it is not unlikely that brevis is preoccupied several 

 times. Until the classification is tlioroughly cleared up it seems 

 preferable to write solida. 



Pleurocera (Io) fluviatilis (Say). 

 Fususfliiviatilis, Say, 1825; lofusiformis. Lea, 1831 ; /. spinosa, Lea, 



1834; /. tenebrosa, Lea, 1H34 ; /. brevis, Antliony, 1860; 



/. spirostoma, Anthony, 1860; /. turrita, Anthony, 1860; 



/. inermis, Anthony, 1860; /. verrucosa, Reeve, 1860 (preocc); 



/. lurida, ' Anth. MS.,' Reeve, 1860; I. gibbosa, ' Anth. MS.,' 



Reeve, 1860; /. rhombica, 'Anth. MS.,' Reeve, 1860; /. recta, 



'Anth. MS.,' Reeve, 1860. 

 Shell of large size, broadly conical, the mid-adolescent whorls 

 subangular at peripherv, and more or less ornamented with nodes 

 which increase in size and complexity on the later volutions, developing 

 on the body-whorl into hollow spines, aperture broadly elliptical and 

 very much produced below, the canal nearly equal in length to the 

 spire; armigera stage completed during early adolescence; liabitat 

 streams. 



