138 THE NAUTILUS. 



Information concerning the breeding habits of Acella are still 

 a desideratum. It occupies the surface in shallow water (one 

 to three feet) in the fall ; but where does it lay its eggs ? None 

 were observed in the fall of 1915 though adults sexually mature 

 were collected. It may be that the animal descends to the 

 pond-weed zones in the winter and lays its eggs on the Potamo- 

 geton and that they subsequently hatch out in the spring. 

 Certainly, as young were found in July which had 3^ whorls 

 and were 10 mm. long, they must have been hatched at the 

 latest in the spring. We are ignorant, also, of whether the 

 maximum growth is completed in one or more years. There 

 is much about this most characteristic Lymnaeid that is still to 

 be learned. 



New York State College of Forestry, 

 Syracuse University. 



NEW LAND SHELLS FROM ALABAMA AND ARKANSAS, WITH NOTE ON 

 POLYGYRA ALBOLABRIS AND P. ZALETA. 



BY GEO. H. CLAPP. 



ViTREA (Paravitrea) conecuhensis n. sp. PI. 5, figs. 5, 6, 7. 



Shell thin, depressed, umbilicate, the umbilicus being about 

 1 mm. in diameter and showing all the whorls ; color light horn, 

 highly polished ; whorls 6, the first five closely coiled, the last 

 rapidly expanding. Surface sculptured with spaced, unequal, 

 radial grooves stopping at the periphery, which is slightly sub- 

 basal. Aperture subtriangular, lower lip slightly flattened and 

 reflected where it joins the columella. Adult shells are tooth- 

 less, but a 3^oung shell of 4^ whorls, 2f mm. in diameter, shows 

 a single pair of small tubercular teeth. 



Diameter 4^, altitude 2^ millimeters. 



Evergreen, Conecuh Co., Alabama. Collected by Herbert H. 

 Smith. 



Types No. 8111 of my collection. Paratypes in collection of 

 Bryant Walker, Detroit, Mich. 



This species resembles Vitrea simpsoni Pils. , but has about one 

 more whorl in the same diameter ; it is also less depressed, and 

 the basal lip is less flattened. 



