LYMN^EIDyE OF NORTH AMERICA. 195 



rated insertions, while in the balance of the specimens examined (pi. 

 XV, fig. E, 1, 3) there is a single band of tissue with two small inser- 

 tions. In several cases the retractors of penis and penis-sac were 

 joined and formed one band of muscle as it entered the columella 

 muscle. The measurements of the genitalia may be tabulated as fol- 

 lows : 





• Penis- 





Prostate 



Rec. sem. 



Penis-sac 



Penis 





Penis. 



sac. 



Vas. def. 



duct. 



duct. 



retractor. 



retractor. 



Shell, 



2.00 



2.25 



6.00 



2.80 



3.00 



1.60 



1.65 



24.50 



1.50 1 



2.60 



6.50 



2.90 



3.00 



3.00 



3.00 



26.00 



1.60 



2.25 



6.50 



2.90 



3.00 



1.75 



1.75 



23.50 



1.50 1 



2.50 



6.00 



2.80 



3.00 



2.00 



2.00 



26.00 



The genitalia of Acella haldemani differ from those of the other 

 Lymnaeidse in the long, flatly cylindrical prostate. 



Range: (Figure 15) Vermont and eastern Ontario west to north- 

 ern Minnesota, south to northern Illinois and northern Ohio. 



The range of haldemani lies on the confines of the Canadian and 

 the upper Mississippian regions, and does not extend for any great 

 distance into either. It is confined to the drainage of the St. Law- 

 rence-Great Lakes and the upper part of the Mississippi River. With 

 the exception of the Minnesota records, the distribution lies within 

 the drainage area of the Great Lakes. It is characteristic of the transi- 

 tion life zone. The records indicate that the species did not take ad- 

 vantage of the Lake Agassiz connection with the Minnesota River; it 

 is possible that it is a new type developed since the Glacial Period. 

 Information is needed concerning the range of this species in north- 

 ern Michigan, Wisconsin and Minnesota and in Canada. 



RECORDS. 



UNITED STATES. 



Illinois: Cedar Lake, Lake Co. (State Laboratory). 



Michigan : Lakes near Grand Rapids and lakes in Grattan, Kent Co. 

 (Currier); Grand Rapids (J. A. McNeil); Reeds Lake, Kent Co. (Kirtland; 

 Walker); Kent and Eaton Counties (Walker). 



Minnesota: Vermilion Lake, Dakota Co. (Grant); Pelican Lake, Crow 

 Wing Co. (Nason) ; Belle Lake and Heath Lake, Wright Co. (Sargent). 



New York: Buffalo, Erie Co. (Buffalo Soc. N. H.) ; Strawberry Island, 

 Buffalo (Letson) ; Squaw Island, Niagara River, Erie Co. (Lewis) ; Mohawk, 

 Herkimer Co. (Lewis); Little Lakes, Otsego Co. (Lewis; Lea); Schuyler's 

 Lake, Otsego Co. (Am. Mus. N. H; Lewis; Binney's fig. 113); Lake Cana- 

 darago, Otsego Co., previous to 1870 (Smith). 



Ohio: Congress Lake, between Portage and Stark Counties (Bland; New- 

 berry; Sterki) ; Sandusky Bay, Erie Co. (Sterki; Walker). 



^hese were fresh specimens, the balance were alcoholic. Dissections 

 No. 2390S. 



