196 PLANORBIS. 



above and below planulate and having an um- 

 bilicus in the centre ; whorls five, subrotund, 

 moderately increasing, separated by a deep 

 suture ; aperture oblique, roundly lunate. 



Diameter 8, alt. 2*6 mill. 



Texas (Cuba ; Vera Cruz, Mexico.) 



I cannot detect any difference between PI. 

 Havanensis and PI. Ldehnanni, and therefore 

 unite them. 



Mr. Binney has considered PJ. graciJe^itus, 

 Gould, a synonym of Liehmanni, but the lat- 

 ter is a higher and smaller species, inhabiting 

 a different district. 



Subgenus PLANORBELLA, Hold. 



10. PLANORBIS CAMPANULATUS, Say. 

 Hald. Monog. p. 9, t. 1, figs. 7—11. 



(43) 



