282 GENUS POLYPHEMUS. (June^' 



co/M;72(?//a gradually incurved towards the tip; ^z/; trun- 

 cated. 



P. glans. — This shell furnished De Montfort with 

 the type of his genus Polyphemus; he refers to Bru- 

 guiere as the first describer of it under the name of Buli- 

 mus glans in the Encycl. Method. The animal has not 

 been described, but we are informed that it lives in the 

 immense marshes formed by the overflow of the great ri- 

 vers that water the vast country of Louisiana. In the 

 sea- islands of Georgia we found them numerous in the 

 marshy districts immediately behind the sand-hills of the 

 coast; in Florida in similar situations, and also on the 

 Oystershell Hammocks, and generally in such situations 

 as are tenanted by Succinea ca?npestris» The colour of 

 the shell on the spire is chesnut-brown, which gradually 

 and very perceptibly becomes paler to the aperture, aper- 

 ture occupying about half the length of the shell. On 

 elevated situations they were small, almost transpa- 

 rent, and of a fragile consistence. It is only in low^ 

 marshy situations, that they attain their greatest size. 



Length two inches and two-fifths — breadth one inch 

 nearly. 



Animal elongated, as long again as the shell, granu* 

 lated; tentacula four, superior ones oculiferous, abruptly 

 deflected at tip, beyond the eyes; inferior ones much 

 shorter, and abruptly deflected at tip; lips, beneath the 

 tentacula, elongated, palpiform, almost as long as the su- 

 perior tentacula, retractile, generally more or less recurv- 

 ed, compressed, attenuated, and acute at tip, and form- 

 ing a considerable interval between their p^pminent bases. 



When the animal is in motion, the elongated lips are 

 used as tentacula to feel the wav. 



