27 



PHYSA ANCILLARIA, Say. 



Plate 3.— Figs. 1—10. 



P. testa subglobosa, luteo-cornea; anfractibus 4 con- 

 vexis: sutura inconspicua: spira brevi, acuta, vel erosa: 

 apertura lata. 



SYNONYMS AND REFERENCES. 



Physa ancillaria, Say. Journal of the Academy of 

 Natural Sciences of Philadelphia, vol. v. p. 124. 



P. ancillaria, Gould. Invert, of Mass., p. 213, fig. 142. 



Physa Sayi, Tappan. Am. Jour, of Science, vol. xxxv. 

 p. 269, pi. 3, fig. 3. 



DESCRIPTION. 



Shell subglobose, with four convex narrow 

 whirls, of which the last is much the largest; 

 suture nearly obliterated; apex acute, but fre- 

 quently truncate-eroded: aperture very wide, 

 more than twice the length of the spire: labium 

 thick. 



Color yellowish or brownish corneous, colu- 

 mella generally white; submargins of the aper- 

 ture frequently reddish. 



Monstrosity. The last whirl with a square 

 shoulder. Fig. 7. 



