OF NORTH AMERICA. 193 



Acella gracilis TRYON, Amer. Journ. Conch., I, p. 257, 1865. CURRIER, 

 Amer. Journ. Conch., I, p. 294, 1865. DALL, Ann. Lye. Nat. Hist., IX, pp. 340, 

 349, 1870. LEWIS, Bull. Buf. Soc. N. H., II, p. 135, 1874. DECAMP, Kent Sci. 

 Inst, Pub. No. 5, 1881. GRANT, Rep. Nat. Hist. Surv. Minn., XVI, p. 483, 

 1888. CHENU, Man. de Conch., II, p. 480, fig. 3545. 



Limn&a haldemani DESHAYES, BINNEY, Journ. de Conch., VII, No. 4, 

 Oct., 1867. TRYON, Con. Hald. Mon., p. 114 (88), 1872. BAKER, Bull. Ills. 

 State Lab. N/ H., VII, p. 103, 1906. STERKI, Proc. Ohio State Acad. Sci., IV, 

 p. 382, 1907. 



Limnaa jayi DUNKER, WALKER, Nautilu's, XXII, p. 18, 1908. 



SHELL: Very slender, thin and fragile; color of periostracum 

 yellowish-white; surface generally dull, growth lines closely set, fine; 

 no spiral sculpture; nucleus consisting of about one whorl which is 

 long-oval in outline and resembles the end of a bullet; when turned 

 to one side the outline of the nuclear and first post-nuclear whorls re- 

 sembles a liberty cap (pi. XLIX, fig. E) ; whorls 5^, very oblique 

 and flat-sided; spire very slender and acute, much longer than the 

 aperture; sutures heavily impressed, bordered by a narrow band indi- 

 cating the position of the previous connected lips ; aperture long-ovate, 

 elongated and narrowed, made continuous by the heavy and raised 

 inner lip; peristome thin, acute, inner lip elevated in some specimens 

 and causing the aperture to be continuous; in other individuals it is 

 attached but not appressed to the parietal wall; the aperture is also 

 twisted to the left and narrowed at its junction with the body whorl; 

 axis gyrate; there is a small umbilical chink; there is no plait on the 

 columella, which is almost straight. 



Length. Breadth. Aperture length. Breadth. 



18.50 3.50 7.25 2.25 mill. 



20.00 3.75 8.00 2.75 " 



19.00 4.00 7.50 2.50 " 



25.00 5.00 10.50 3.00 " 



24.00 5.00 10.00 3.00 " 



TYPES: Not in Jay collection (vide letter from Mr. L. P. Grata- 

 cap, Amer. Mus. Nat. Hist.). 



TYPE LOCALITY : Lake Champlain. 



ANIMAL: Yellowish, flecked with fine white dots, which become 

 larger on sides of body and edge of mantle; under side of foot bor- 

 dered by a dark margin ; tentacles small ; foot broadly long-ovate and 

 shorter than aperture, one specimen measuring as follows : shell, 22.50 

 mill., aperture 11.00 mill., foot 7.00 mill. ; the shell and animal are in 

 life almost transparent, the organs showing plainly through the shell, 

 especially those of the digestive system. 



