412 ILLINOIS STATE ACADEMY OF SCIENCE 



Pomatiopsis laphlaria (Say). Eare. The fossil form 

 has deeper sutures than the recent form; specimens from 

 loess-like deposits in northwestern Illinois (Stephen- 

 son Co.) are midway between the recent and marl speci- 

 mens in this respect. The Joliet specimens are rather 

 more widely umbilicated than the recent form. 



Amnicola leiglitoni Baker. Common. Leiglitoni ap- 

 pears to be the common Amnicola of the Pleistocene, 

 replacing limosa in many places, and to which it has 

 previously been referred. There is some variation in 

 the form of the aperture, a number of individuals hav- 

 ing more shouldered whorls than the typical form as 

 described from Ohio, 



Amnicola lustrica gel'ida Baker. Abundant and vari- 

 able. The Joliet Amnicolas are nearer typical lus- 

 trica than the lot from near Morris (the original locality 

 for gelida), the spire being shorter and the body whorl 

 wider. All have the thickened lip and more acute spire 

 with deep sutures characteristic of gelida. (See Baker, 

 Nautilus, Vol. XXXV, p. 222, 1921.) 



PULMONATE GASTEOPODS 



Physa ivarreniaua Lea. Common. The marl ma- 

 terial is referred with some hesitation to ivarreniana. 

 There is considerable variation in the height of the spire 

 and in the width of the body whorl, the variation being 

 toward an ancillaria type of shell. 



Physa gyriua Say. Several small specimens are 

 referred to this protean species, probably washed into 

 the localit^^ from some quiet pond-like area. 



Planorhis trivolvis Say. A young individual only. 



Planorhis antrosus Conrad. The form without spi- 

 ral striation is rare in these marl deposits. 



Planorhis antrosus striatus Baker. The majority of 

 the marl antrosus are referable to the striate form. 



Planorhis campanulatus ferrissi New Var. The shells 

 from the Joliet marls are different from the recent form 

 of typical cam.panulatus. The whorls are not as high, 

 giving the shell the appearance of having a greater di- 

 ameter and more whorls. The marl form is also smaller 

 on the average and the aperture is not as widely cam- 



