OF NORTH AMERICA. 403 



Specimens in the Lea collection (Smith. No. 118655) are similar 

 to specimens in the Philadelphia Academy (No. 58703) which were 

 received from Mighels, and which correspond with his figures and de- 

 scriptions, and it is these forms which must be taken as correctly 

 representing Mighels' species. Specimens in the collection of Mr. 

 Bryant Walker, which were received from Mighels, are figured on 

 plate XLII, figures 23-25. The material examined is very uniform and 

 the species appear to be very distinct. An examination of the axis 

 shows that decollata is a member of the catascopium group of the 

 subgenus Stagnicola, and was not correctly placed in Radix by Binney, 

 Ball, Tryon and other conchologists. The peculiar swelling out of 

 the periphery of the body whorl in decollata will at once distinguish it 

 from all related forms. The writer has not seen specimens from Con- 

 necticut or from different parts of Canada, and the records of Lins- 

 ley, Bell and others in which decollata is cited from these localities is 

 greatly to be questioned. They will probably be found to be forms 

 of catascopium or oronensis. 



Galba sumassi (Baird). Plate XLI, figures 11-17. 



Limnaa sumassi BAIRD, Proc. Zool. Soc., p. 68, 1863. CPR., Rep. Brit. 

 Assoc., p. 673, 1864. BINNEY, L. & F.-W. Sh. N. A., II, p. 43, fig. 56, 1865. 

 TRYON, Amer. Journ. Conch., Ill, p. 196, 1867. CPR., Smith. Mis. Coll., p. 159, 

 1872. SOWB., Conch. Icon., XVIII, Limn., sp. 34, 1872. STEARNS, Proc. Nat. 

 Mus., XIV, p. 101, 1891; XXIV, p. 291, 1901. WHITEAVES, Ottawa Nat, XX, 

 p. 115, 1906. 



Limnophysa sumassi TRYON, Amer. Journ. Conch., I, p. 251, 1865. CALL, 

 Bull. U. S. Geol. Surv., II, p. 371, 1884 (part). 



Lymnea sumassi LORD, Nat. in Brit. Col., II, p. 363, 1866. 



Limnceus sumassi CLESSIN, Kiister, Conch. Cab., p. 387, taf. 53, fig. 4, 1886 

 (figure poor). 



Limnaa nuttalliana var. sumassi COOPER, Proc. Cal. Acad. Sci., IV, p. 96, 

 1870 (part). 



Lymn&a catascopium var. sumassi DALL, Alaska Moll., p. 78, 1905 (part). 



SHELL: Narrow, elongated, attenuated, fusiform in some speci- 

 mens, varying from thin to rather solid; periostracum light, whitish 

 horn, with two or three rest period bands; surface shining, lines of 

 growth coarse and heavy, wrinkled and crowded about the aperture, 

 crossed by very heavy impressed spiral lines ; nuclear whorls rounded, 

 smooth, dark brown color, in size about as in catascopium; whorls six, 

 flatly rounded, slowly enlarging; last whorl somewhat flat-sided nor- 

 mally; spire rather long, pointed, a trifle longer than the aperture; 

 sutures well impressed ; aperture elongate-ovate, somewhat semi-lunate, 

 a little effuse anteriorly; peristome thin, acute, bordered within by a 

 narrow black band which marks a rest-varix; parietal wall with a 



