178 THE CHICAGO ACADEMY OF SCIENCES. 



'Testa imperforata, ovato-oblonga, tenuis, pallide fusca, subtiliter 

 striata, striis spiralibus confertis regulariter decussata (italics are the 

 author's); spira conica et acutiuscula; anfr. 4 convexiusculi, utlimus 

 maximus; apertura elliptica, antice amplior, 5/8 out 5/9 longitudinis 

 aequans; columella brevissime intorta; peritr. acutum. Long. 8/9, 

 diam. ^/ 2 mill. Succinaeformis, parum nitida." 



This interesting little species will doubtless be found to be a 

 common inhabitant of the ponds and lagoons of Cuba. 



Genus RADIX Montfort. 1810. 



1810. Radix MONTFORT, Conch. Syst., II, p. 266. Type Helix auricularia L. 



(sole example). 



1819. Gulnaria, LEACH, Proofsheets, pp. 146, 148 ; fide Turton, Man., p. 117, 1831. 

 1840. Gulnaria, GRAY'S TURTON, p. 232 (type L. auricularia Linne). 

 1847. Gulnaria GRAY, P. Z. S., p. 180 (type L. auricularia, Linne). 

 1855. Neritostoma H. & A. ADAMS, Genera Rec. Moll., II, p. 253, 1st sp. L. 



auricularia (Linne). Not of Morch, 1864. 



1864. Radix MORCH, Vidensk. Meddel. Kjob., p. 302. 



1865. Radix BINNEY (part), L. & F. W. Sh. N. A., II, p. 30. 

 1870. Radix DALL, Ann. Lye. Nat. Hist., N. Y., IX, p. 349. 



1874. Radix HARTMAN and MICHENER, Conchologia cestrica, p. 62. 



1876. Radix MEEK, U. S. Geol. Surv. Terr., IX, p. 532. 



1880. Radix CR. & FISCH., Mis. Scient. Mex., II, p. 52. 



1884. Radix TRYON, S. & S. Conch., Ill, p. 101. 



1905. Radix DALL, Alaska Mollusks, p. 64. 



1908. Radix BAKER, Science, N.-S., XXVII, p. 943. 



SHELL: Broadly ovate or rounded; spire generally short, last 

 whorl very large, globose, somewhat expanded or even campanulate; 

 outer lip simple, without internal thickening; columella strongly 

 twisted in the earlier whorls, but the twisting frequently concealed by 

 a reflexed inner lip, which may be conspicuously elevated and form a 

 large, open umbilical chink; sculpture as in Lymncea (pi. XVIII, 

 fig. 9). 



ANIMAL : Not differing essentially from Lymncea externally. 



JAW : Wide and low with a heavy, broadly rounded median pro- 

 jection on the ventral surface (pi. VI, fig. D). 



RADULA: First laterals tricuspid; balance bicuspid (pi. VII, 

 fig. C). 



GENITALIA: The penis-sac is large, the penis is longer than the 

 penis-sac and does not exceed the vas deferens in diameter; there is 

 one penis-sac retractor which enters the penis-sac by a large, bifid 

 splitting of the muscle; penis retractor narrow, about as long as the 

 penis-sac retractor; it enters the columella muscle near the point of 

 insertion of the penis-sac retractor; prostate not large, regularly pyri- 



