OF NORTH AMERICA. 371 



Limnophysa wormskioldi TRYON, Amer. Journ. Conch., I, p. 254, 1865. 



Limnaa vahlii, Jun., MORCH, Prod. Moll. Gron., No. 135. 



Limncea senegalensis BECK, Index, p. Ill, 1838 (nude name) ; MORCH, 

 Aimer. Journ. Conch., IV, p. 35, 1868 (footnote). 



Limncea vahlii var. malleata MORCH, Moll. Gron., p. 76, 1857. STEENSTRUP, 

 Mai. Blatt, n. s., I, p. 17, 1879. MORCH, Amer. Journ. Conch., IV, p. 35, 1868. 



SHELL: Thin, sometimes translucent, ovate-oblong or elongated; 

 periostracum pale yellowish or greenish horn, sometimes reddish ; sur- 

 face shining, growth lines very fine, crossed by fine impressed-spiral 

 lines giving the surface a delicately waved appearance; whorls 5^2 

 to 6, very convex, the body whorl very large and obese ; sutures deeply 

 impressed; spire acutely pyramidal, generally a trifle longer than the 

 aperture; aperture elongate-ovate or elliptical, sometimes a trifle ex- 

 panded, outer lip thin, with a slight varical thickening in adult shells; 

 inner lip rather wide, spreading over the parietal wall in a wide, more 

 or less heavy white callus; axis slightly twisted with a weak, oblique 

 plait; there is a small, narrow, umbilical chink. In some scalar speci- 

 mens the umbilicus is rather widely open; the varical bands on the 

 shell number two or three. 



Length. Width. Aperture length. Width. 



22.00 9.00 11.00 .... mill. (Morch, typical). 



18.50 9.00 9.00 4.50 " St. Michaels. 



15.50 7.50 7.00 3.50 " Alaska. 



16.00 7.50 9.00 4.50 " " 



14.50 7.00 7.00 4.00 " 



16.00 6.50 6.00 3.25 " (Scalariform). 



18.25 9.00 9.10 4.75 " Yukon Terr. 



19.10 9.50 10.00 4.75 " " " 



11.00 5.50 5.50 2.75 " Gronlandica ex Morch. 



15.00 7.00 .... .... " Wormskioldi ex Morch. 



18.00 9.00 .... .... " Malleata ex Morch. 



15.00 7.00 .... .... " Solidula ex Morch. 



TYPES: The types of vahlii and its varieties are believed to be 

 in the University Museum of Copenhagen. 



TYPE LOCALITY: Vahlii, Amaraglik; molleri, Tunnundliarbik ; 

 zvormskioldi, Wormskiold; solidula and malleata, exact locality not 

 stated. 



ANIMAL : "Animal grayish-green with minute yellow white dots" 

 (Moller, teste Morch). 



JAW, RADULA and GENITALIA: Not examined. 



RANGE: (Figure 39) Greenland west to Alaska, south to Great 

 Slave Lake and Ungava. 



Vahlii is a Boreal species of wide distribution, extending north- 

 ward from about the 58th degree of north latitude. It will probably 



