LYMNJEIDJE OF NORTH AMERICA. 239 



sac retractor. (PL XIV, fig. F.) The normal form and position of 

 the retractor and protractor muscles appears to be as shown in (1) 

 of Fig. F. 



Several measurements of the genitalia are given below. (Dissec- 

 tions Nos. 23151, 23165, 23166) : 



Penis Penis- 

 Shell. Locality. 

 6.00 Cayuga Lake 

 7.00 

 7.00 



8.00 Maine 

 6.20 " 



In some specimens the penis is slightly enlarged toward the head. 

 (Plate XI, fig. B, 1.) 



The genitalia of umbilicata closely resemble those of parva. 

 RANGE (Figure 21) : Northern Maine and southern Ontario to 

 Rhode Island and New Jersey, west to New York and southeastern 

 Michigan. 



The range of umbilicata is imperfectly known, as it has probably 

 been identified as humilis, which it somewhat resembles. The records 

 at present known show it to range from Maine to Michigan and south 

 to New York and New Jersey, which indicates that it is an inhabitant 

 of the Canadian and Nova Scotian regions. It is characteristic of the 

 humid divisions of the Canadian and Transition life zones. Until more 

 specimens have been examined from different parts of the United 

 States no generalizations can be made. Umbilicata probably inhabits 

 a large portion of the northern part of the United States. 



RECORDS. 



UNITED STATES. 



CONNECTICUT : Small stream emptying into Farmington River, Unionville, 

 Hartford Co. (Baker). 



MAINE: Buckfield, Oxford Co. (J. A. Allen); Woodland, Aroostook Co. 

 (Nylander) ; Fox Island, Penobscot River, Knox Co. (Jackson). 



MASSACHUSETTS: New Bedford, Bristol Co. (Adams) ; Brook near Cabot's 

 Park, Newton; Charles River above Watertown, Middlesex Co. (Baker) ; Swamp- 

 scott, near Lynn, Essex Co. (Tufts) ; Southborough, Worcester Co. (Bos. Soc. 

 N. H.) ; Salem, Essex Co. (True) ; Essex Co. (Russell) ; Westfield, Hampden 

 Co. (Smith. Coll.). 



MICHIGAN: Otter Lake, Lapeer Co. (Walker). 



NEW JERSEY: Drainage ditches east of Burlington, Burlington Co. (Baker; 

 Pilsbry). 



NEW YORK : South end Cayuga Lake, near Ithaca, Tompkins Co. ; Erie 

 Canal ; Maplewood Park, Rochester, Monroe Co. ; 4 miles south of Cayuga, 

 Cayuga Co. (Baker) ; Charlotte Lake, Columbia Co. (Lea). 



RHODE ISLAND: The Fountain, Pawtucket, Providence Co. (H. F. Carpen- 

 ter) ; Rhode Island (Walker). 



