FAMILY LIMNIAD^E PHYSA. 81 



Physa ELONGATA. 



PLATE XXXVI. FIG. 346. 



P. elongala. Say, Joum. Acad. Nat. Sciences, Vol. 2, p. 171. 

 P. id. Adams, Am. Joum. Science, Vol. 40, p. 269. 



P. id. Gould, Invertebrata of Mass. p. 214, fig. 143. 



Description. Shell sinistral, very fragile, diaphanous, oblong. Whorls six or seven, polished. 

 Spire tapering, acute at tip. Suture slightly impressed. Aperture not dilated, attenuated 

 above, about half as long as the shell. Columella much narrowed near the base, so that the 

 view may be partially extended from the base towards the apex. 



Color. Pale yellowish. Animal dusky : head above orange. 



Length, 0-5-0' 7. Diameter, 0'2. 



Common from Maine westwardly : usually found in stagnant pools. 



(EXTRA-LIMIT AL.) 



P. pomilia. (Conrad, Am. Jour. Vol. 25, p. 243.) Volutions four, polished; spire short, conical; 



body-whorl ventricose ; aperture patulous. Color, corneous. Alabama. 

 P. intcgra. (Hald. Monog.) Shell oval, of five very convex whorls; apex pointed; suture very 



deep ; aperture oval, wide posteriorly ; peritreme continuous ; no fold on columella. Color, pale, 



with white varicose bands. Length, 0-5. Indiana. 

 P. concolor. (Id. I.e.) Shell oval; spire produced, with the apex pointed; whorls four, convex; 



aperture oval, narrow; fold on the columella distinct. Color, honey-yellow. Length, 0*23. 



Oregon. 

 P. sayii. (Tappan, Wheatley's Catalogue.) 

 P. globosa. (Hald. Ac. Sc. Vol. 8, p. 200.) Shell globose, translucent; spire short and rounded; 



aperture very wide, occupying more than one-half of the entire area of the shell; fold well marked. 



Length, . 3. Virginia. 



SECTION OPERCULATED PULMOBRANCHIA 



Animal provided with a foot for crawling. No gills, but a pulmonary cavity communicating 

 externally with the air by a large solution of continuity placed above the head. Two 

 tentacles. Generative organs upon different individuals. All terrestrial. Shell external, 

 complete, spiral, globular or conic ; a calcareous or horny opercle. 



Obs. None of this section are found in this or the adjoining States. 

 Fauna — Part 6. 1 1 



