66 ZONITIDAE 



MESOMPHIX CUPREUS (Rafinesque) 



The copper-colored shell of the snail Mesomphix cupreus 

 attains a diameter of about an inch (24 mm.). In specimens 

 from Illinois the height of the shell is approximately two-thirds 

 _ of the diameter. The depressed 



although somewhat dome-shaped 

 spire has 4% whorls. Of these 

 the outermost, or the body whorl, 

 is widely expanded transversely. 

 The base of the shell is rounded 

 and has a deep, though not wide, 

 umbilicus. The transversely ellip- 

 tical aperture, pearly within, has an indistinct bluish-white 

 callus near the edge of the lip. The lustrous shell is of a rich 

 copper or yellow color with shades of green and brown. 



The animal is black or blue-black in color; the head, neck 

 and eye peduncles are darker than the rest of the body. The 

 base of the foot is whitish. The eye peduncles, which are rather 

 short as compared with the length of the body, are set wide apart. 

 This snail, once known as Zonites fuliginosa and Omphalina 

 cuprea, is abundant in southern Illinois, ranging as far north 

 as Calhoun and Moultrie counties. It is common to abundant 

 along the river valleys, particularly on the limestone bluffs of 

 the Mississippi River. Its most favorable habitat is in forests 

 of oak, elm, hickory, walnut and ironwood in which there is 

 often a sprinkling of pine. Such situations afford a good cover 

 of logs and general forest debris, where snails of the species 

 cupreus may find concealment. 



Specimens of Illinois Mesomphix cupreus differ from those 

 that occur in Kentucky, Tennessee, Indiana and Ohio in being 

 more globose. The spire of the Kentucky specimens is relatively 

 flat, and the diameter of the shell is almost twice the height. 

 The Illinois shells more nearly resemble the form found in 

 Missouri, Arkansas and Oklahoma. In the Illinois shells the 

 bluish-white callus found just within the lip is not so distinctly 

 marked as in the Kentucky and Tennessee specimens. Mesom- 

 phix cupreus reaches its greatest development in Tennessee, in 

 the Great Smoky Mountain region, where also occur several 

 varieties or races of cupreus which are absent from the Illinois 

 fauna. 



