PUPILLIDAE 



93 



Family PUPILLIDAE 



The elongated oval shells of snails belonging to the family 

 Pupillidae are small, none exceeding one-fourth inch (5.5 mm.) 

 in height. The outer lip or peristome of the turreted shell is 



Angular Lamella 

 Parietal Lamella 



COLUMELLAR LAMELLA 



Upper Palatal Fold 



Lower Palatal Fold 

 Basal Fold 



usually, though not always, provided with projections called 

 folds, lamellae or denticles. Some species of this family have 

 few folds, lamellae or denticles; others have many. 



These projections have been called teeth, but this term is 

 incorrect, since the folds are in no way teeth. The animal bites 

 or chew^s food by means of the lingual ribbon (see page 7). 

 The obstructions in the aperture should always be called folds, 

 lamellae or denticles in order to differentiate them from this 

 organ. As the projections have been given definite names and 

 as they always occur in the same position in the different species, 

 they form very valuable means of identification. The positions 

 of the principal folds and their names are shown in the figure 

 above. The accessory, smaller folds have been omitted to avoid 

 confusion. The principal lamellae are the angular, the parietal 

 and the columellar. The principal folds are the upper palatal, 

 the lower palatal and the basal. 



The animals of the Pupillidae are small. The body of each 

 is bluntly rounded before and tapered behind. The eye peduncles 

 are long, and the tentacles short and thick. The animals vary 

 in coloration. In each species, the body of the animal when 

 extended from the shell is about as long as the shell itself. The 

 animal and shell of a member of this family, Gastrocopta con- 

 tracta, are pictured on the next page. 



