SUCCINEIDAE 



121 



Family SUCCINEIDAE 



The Succineidae, the amber snails, may be recognized by 

 their thin, yellowish, oval shells with very large apertures and 

 small spires. Pictured below is a specimen of Succinea avara. 



The animal, which cannot retract completely within the 

 shell, is bluntly rounded before, tapering at the posterior 

 extremity. The eye peduncles are short and thick; the tentacles 

 are very short. The body, which varies from yellowish to black, 

 is m.ottled and streaked. The same animal may be dark colored 

 in spring and yellowish in summer and fall. 



Genus SUCCINEA Draparnaud 



The Succineidae family contains but one genus, Succinea., 

 represented in Illinois by five species and six races. 



Key to Species 



1. Aperture round, not much higher than wide, occupying three- 



fifths length of shell avara, p. 124 



Aperture ovate, occupying three-fourths to four-fifths length 

 of shell, p. 122 ■ 2 



2. Shell ovoid, somewhat inflated; aperture ovate; spire broad, 



p. 122 3 



Shell much elongated, narrow; aperture narrowly ovate; 

 spire acute, p. 125 4 



3. Aperture regularly ovate; color greenish or yellowish 



ova/is, p. 122 



Aperture obUquely ovate, expanded at lower part; color 

 amber concordia/is, p. 123 



4. Aperture occupying three-fourths length of shell, little ex- 



panded at lower part retusa, p. 125 



Aperture occupying four-fifths length of shell, notably ex- 

 panded at lower part salleana, p. 127 



