PUPILLIDAE 



99 



Few conchologists take the trouble to cut open the shells of 

 small species, which is the only method by which these two 

 forms of contracta described here can be distinguished. 



GASTROCOPTA HOLZINGERI (Sterki) 



The snail familiarly known as Holzinger's Gastrocopta has 

 a white glassy shell which is little more than one-sixteenth inch 

 (1.7 mm.) in height. Cylindric in shape, the shell has 5 rounded 

 whorls, regularly decreasing in size as they 

 approach the apex, fig. A. The shape of the 

 aperture is round, not triangular as that in 

 Gastrocopta contracta. The lamellae and folds 

 of holzingeri differ very markedly from those 

 of contracta. The parietal lamella, which is 

 forked in front, somewhat resembles the letter 

 Y, fig. B. The basal fold is large, and the 

 lower palatal fold is pyramidal rather than 

 rounded in shape. The columellar lamella is 

 larger and more conspicuous in holzingeri than 

 the same lamella in contracta. 



Gastrocopta holzingeri apparently is 

 a rare species in Illinois. Records of it 

 are at present known from only four 

 counties in the state: Will and La Salle 

 in the northern part, Hancock in the cen- 

 tral area and Jackson in the southern 

 zone. 



The habitat of this snail, similar to 

 that of Gastrocopta contracta, is on wooded floodplains where 

 moisture is abundant; in forests and woodlands of sycamore, 

 elm, oak, basswood and hickory; and on limestone bluffs. 



The young conchologist often wonders about the person 

 whose name follows a specific designation. Dr. Victor Sterki, 

 who is the author of Gastrocopta holzingeri, was a practicing 

 physician living in New Philadelphia, Ohio. Unlike the many 

 naturalists who prefer to study the large species. Dr. Sterki was 

 drawn to the study of the minute forms of moUusks. 



The tiny pupoids first attracted his attention, and he made 

 a careful study of the American species, finding several which 

 had been overlooked by other conchologists. 



