108 PUPILLIDAE 



Genus PUPOIDES Pfeiffer 



Most species of the family Pupillidae found in Illinois 

 have folds or lamellae in the shell aperture. However, two 

 species, one of which belongs to the genus Pupoides and the 

 other to the genus Columella, lack these formations. In the two 

 other Illinois genera of this family, Gastrocopta and Vertigo, 

 the folds and lamellae which are present serve as valuable 

 distinguishing characteristics. A distinguishing mark of the 

 genus Pupoides is the reflected lip or peristome of the shell, 

 which forms a thick, wide margin to the aperture. 



PUPOIDES MARGINATUS (Say) 



The shell of the species known as Pupoides marginatus has 

 a rounded aperture with a peristome that is broadly reflected. 

 The aperture is entirely without lamellae or folds. The brown 

 shell of this species is about one-fourth inch 

 (5.5 mm.) in height. It has 6 whorls and a 

 very small umbilical perforation. The shell of 

 Pupoides marginatus is elongated and tapers 

 regularly to a point. No other land snail of 

 Illinois resembles this species, which is the only 

 species of its genus found in the state. 



The animal of the species marginatus has 

 long and slender eye peduncles and very short 

 tentacles. The color of the neck, head and eye 

 peduncles is black; the posterior portion of 

 the animal is lighter. 



Pupoides marginatus is widely distributed 

 over Illinois. It has been recorded from numerous counties. 

 It is particularly abundant in the counties of McHenry, Madi- 

 son, Randolph, Jackson, Adams and Calhoun. Its most common 

 habitat is on wooded bluffs and hillsides of rivers and streams, 

 where oak, elm, basswood, hickory and sometimes pine are 

 present. Occasionally this species is found in grass and on rail- 

 way embankments. 



Every day I used to ride out alone along the seashore, 

 where I dismounted, and filled my pockets with all sorts of 

 pebbles, snail shells, and sea shells of great rarity and beauty. 

 — Benvenuto Cellini, Autobiography 



