117 



grooves above it, so as to appear double ; color pale, with several 

 revolving reddish-brown lines ; aperture rounded : labrum thick- 

 ened, somewhat recurved; a slight but very obvious sinus at base, 

 and another very slight, more obtuse one near the junction with 

 the preceding whorl ; umbilicus none. 



Length nine-tenths of an inch. 



Mr. Titian Peale found this handsome and curious shell in 

 great abundance in the fresh water lakes of the Florida Keys. It 

 is most certainly a fresh water shell, yet it is destitute of an epi- 

 dermis. The labrum thickens with age ; the operculum is orbicu- 

 lar, and so small as to admit of the animal retiring one half the 

 length of the shell. It differs from Ilelama, 3Ielanopsis, and 

 Pirena, in the rotundity of the aperture, the thickened labrum, 

 and comparative smallness of the operculum. 



The tenfacula of the animal are two in number, and the eyes are 

 placed a little above their exterior base. 



[J. A. N. S., vol. V. p. 129, et seqq. Nov., 1825.] 



Fusus FLUViALis. — Shell fusiform, olive-green or brownish ; 

 spire much elevated, gradually tapering; volutions nearly six, 

 wrinkled across, and with a series of elevated undulations on the mid- 

 dle ; suture consisting only of an impressed line ; aperture somewhat 

 fusiform ; within whitish, more or less with dull reddish, and with 

 several lines of that color, sometimes confluent ; labrum on the 

 inner margin immaculate, edge undulated ; canal rounded at tip ; 

 columella very concave. 



Length one and eight-tenth inches ; aperture nineteen-twentieths 

 of an inch ; greatest breadth nineteen-twentieths of an inch. 



Professor Vanuxem found this curious and highly interesting 

 shell on the north fork of the Holstein River, near the confluence 

 of a brook of salt water. From the name of the genus it might 

 reasonably be supposed to be a marine shell, but it has never been 

 discovered on the coast, and seems to be limited to a very small 

 district of the Holstein River, in company with Unio cariosus, sul- 

 tentus, nobis, Melania subglohosa, nobis, and no doubt other flu- 

 viatile shells. When the inhabitant becomes known it may autho- 

 rize the formation of a new genus, but there appear no characters 

 in the formation of the shell that would really distinguish it from 

 Fusus. 



