ENDODONTIDAE 



89 



body, the whole animal being in front of the shell, the rather 

 short eye peduncles standing almost vertical and the tentacles 

 pointing almost straight ahead. 



This species is distributed throughout Illinois. Its natural 

 habitat is in river valleys wooded with oak, walnut, elm, bass- 

 wood and sassafras, or in floodplain areas wooded with oak, 

 elm and hickory. It is a woodsnail and it lives only rarely in 

 more exposed places. Near Quincy it has been found in grass, 

 an unusual habitat. Occasionally it has been collected from 

 cut-over lands among trees of second growth oak, walnut and 

 hickory. 



HELICODISCUS SINGLEYANUS INERMIS 

 H. B. Baker 



The recently described snail Helkodiscus singleyanus inermis 

 is very small, its waxy, yellowish shell about one-sixteenth inch 

 (2.25 mm.) in diameter. Only one species of snail, Hawaiia 

 minuscula, is known from Illinois with 

 which it might be confused. Of about 

 the same size, singleyanus inermis differs 

 from minuscula in having a broader, 

 shallower umbilicus. The base of the 

 singleyanus inermis shell is more nearly 

 flat, and the surface is smooth like 

 paraffin and without the fine sculpture 

 of minuscula, which renders that shell 

 silky in appearance; singleyanus inermis 

 has no spiral lines. 



Helicodiscus singleyanus inermis is 

 widely distributed throughout Illinois, 

 but the records are somewhat scattered. 

 Its small size has doubtless caused it to be overlooked. In some 

 collections it has probably been confused with Hawaiia minus- 

 cula, and it may have been reported under that name. Helico- 

 discus singleyanus inermis appears to be most common in the 

 northern and eastern parts of the state, where it may be found 

 in forest debris, under leaves and in old piles of washed material. 

 It is rarely found living in old logs and under loose bark. 



Helicodiscus singleyanus singleyanus, the typical race of the 

 species, has not been reported from Illinois. 



