LYMNZIDZ OF NORTH AMERICA. 201 
RapuLa: With bicuspid lateral teeth (pl. VI, fig. N). 
GENITALIA: Penis shorter than penis-sac; prostate short, elon- 
gate-ovate, its proximal portion rather roundly pointed as it joins the 
duct; receptaculum seminis generally ovate, rarely round; the first 
accessory albuminiparous gland is ovate and is placed lower down on 
the oviduct than in Stagnicola (pl. XI, fig. A). 
This subgenus contains the smaller Lymnzeas which have a shell 
without strong spiral sculpture. They exhibit terrestrial habits to a 
much larger extent than do any of the other groups of Lymnezeas, being 
found usually on wet banks or bars of mud, quite out of the water. 
The formation of the inner lip is quite peculiar and will at once dis- 
tinguish these small species from their larger relatives. The subgenus 
is widely distributed, being found from the West Indies and southern 
Mexico to the Arctic regions. Its maximum development is reached 
in the southwestern portion of the United States. 
Galba truncatula (Muller). Plate XX VII, figures 1-4 
Buccinum truncatulum MU.iErR, Verm. Terr. et Fluv., II, p. 130, 1774.— 
BAKER, Science, N. S., XX VII, p. 943, 1908. ; 
Limneus minutus DRApARNAUD, Tableau, p. 51, 1801; Hist., p. 53, pl. 3, 
figs. 5, 6, 1805. 
Limnea truncatulus HALDEMAN, Bos. Journ. N. H., IV, p. 468, 1844. 
Limnea truncatula Woopwarp, P. Z. S., 1856, p. 185; Manual, p. 399, 
1856.—CARPENTER, Rep. Brit. Ass., 1856, p. 222—Gray, Ann. Nat. Hist., XIX, 
p. 408, 1857—Morcu, Amer. Journ. Sci., IV, p. 33, 1868.—Grezons, Journ. Conch., 
ITI, p. 129, 1879.—Cressin, Mal. Blatt., N. S., I, p. 20, 1879; Mal. Blatt. N. S., 
III, p. 77, 1881—JorpAn, Nova Acta Ksl. Leop. Carol.-Deutschen Akad. Natur., 
XLV, p. 367, 1883. 
Lymnea (Galba) truicatula Dati, Land and Fr. W. Moll., p. 72, fig. 49, 
1905 (part). 
Limnea humilis Dati, Proc. Nat. Mus., VII, p. 343, 1884; Rep. Seal. Inves., 
III, p. 544, 1899.* (?) 
SHELL: Small, turreted, ovate-conic or oblong-conic, rather 
solid; periostracum light yellowish-horn, sometimes darker; surface 
shining, lines of growth close-set, conspicuous; spiral striation absent 
or only very slightly developed; nuclear whorls 114 in number, light 
horn colored; in outline the first whorl is very small, while the second 
is very large, flattened, wide, and convex; the sculpture is minutely 
substriate under a very high power but appears of a satin finish char- 
acter under a low power (pl. XLIX, fig. D); whorls 5-6, convex, 
roundly inflated, roundly shouldered above, gradually increasing in 
diameter; body whorl occupying about half the length of the shell, 
somewhat ventricose ; spire conic, turreted, more or less acute; sutures 
1Only a few references, chiefly from American sources, are included above, 
Iuropean citations would occupy several pages. 
