NEIIITELLA. 



103 



side ; peritreme continuous and free ; inner lip septiform, tlie margin 

 united to tlie inner portion of the peritreme, slightly arched in the 

 centre, and denticulated. 

 (No American species.) 



Subgenus Alima, Recldz. — Shell depressed, suborbicular, with the 

 upper extremity of the outer margin prolonged into a lateral wing ; 

 spire subposterior and lateral ; inner lip septiform, margin finely 

 denticulate. 



(No American species.) 



Subgenus Neripteron, Lessox. — Shell catilliform, with the two ex- 

 tremities of the outer margin prolonged into lateral auricles ; spire 

 subposterior and lateral ; inner lip septiform ; margin finely den- 

 ticulate. 



(No American species.) 



Operculum of 

 Neritella reclivata. 



Greatest diameter 



Neritella reclivata, Say. — Shell thick, strong, globose-oval, 



greenisli-olive, with numerous approximate, parallel. 

 Fig. 205. irregularly undulated green lines across the volutions ; 



volutions about three, the exterior 



one occupying nearly the whole Fig. 206. 



shell ; spire very short, obtuse at 



the apex, and frequently eroded to 



a level with the superior edge of 



the body whirl ; mouth within blu- 

 Neritella reclivata. ish-white ; labrum acutely edged ; 



labium callous, minutely crenated 

 on the edge, and with a small tooth near the middle, 

 nineteen-twentieths of an inch ; greatest transverse diameter four-fifths of 

 an inch. 



Inhabits East Florida. Cabinet of the Academy and Philadelphia 

 Museum. 



Animal pale or less distinctly lineated, or clouded with black ; foot 

 rounded, almost orbicular, hardly as long as the shell is broad ; above 

 with four more or less distinct, black, parallel lines ; rostrum dilated, trun- 

 cated, tip with four black lines, a black baud connecting the eyes ; eyes 

 prominent, appearing to be placed on a tubercle at the outer base of the 

 tentacula, black, with a white orbit ; tentacula with darker or black lines, 

 setaceous, and longer than the breadth of the rostrum ; beneath im- 

 maculate. 



I found this species in great plenty, inhabiting St. John's River in East 

 Florida, from its mouth to Fort Picolata, a distance of a hundred miles, 

 where the water was potable. It seemed to exist equally well where the 

 water was salt as that of the ocean, and where the intermixture of that 

 condiment could not be detected by the taste. Its movements are re- 

 markably slow. (Sa>/.) 



