AMERICAN SPECIES OF VERTIGO. 145 



wards the subtriangular small aperture. Shell thin, delicate, 

 of pale horn color, as is the palatal wall and margin; the 

 latter simple and straight, with a very slight, thin callus inside, 

 lamellse 3, whitish, rather small: one apertural [parietal], one 

 columellar, longitudinal, and the inferior palatal; sometimes 

 there is also a very small superior palatal. Length 1.5, diam. 

 0.8 mm." (Sterki). 



Length 1.45, diam. 0.8 mm. ; nearly 5 whorls. 



Length 1.53, diam. 0.85 mm. 



Florida: Mosquito Island, Volusia Co., type loc., Oscar B. 

 and G. W. Webster; Grassy Key, Eaybon. Alabama: Ever- 

 green, Conecuh Co., H. H. Smith. Louisiana: S.-W. cor. 

 Madison Parish, Bayou Macon, C. B. Moore. Arkansas : Keller 

 Place Landing, Ouachita R., Calhoun Co., C. B. Moore. Texas : 

 Guadalupe B. near New Braunfels, Ferriss and Pilsbry. 



Vertigo ascariana STERKI, Proc. A. N. S. Phila. 1890, p. 33 ; 

 reprinted in BINNEY, 4th Suppl. Terr. Moll, v, Bull. M. C. 

 Zool. xxii, 1892, p. 197, fig. , Nautilus iii, 1890, p. 136 ; iv, 

 1890, p. 39, pi. 1, f. 5. PILSBRY, Proc. A. N. S. Phila. 1906, 

 p. 147. CLAPP, Nautilus xxviii, 1915, p. 137, pi. 6, f. 8. 



The surface is delicately but rather sharply and regularly 

 striate, most conspicuously so on the penult whorl. The colu- 

 mellar lamella is rather blunt and thick, the lower end vertical, 

 the upper slanting slightly inward. The parietal lamella is 

 short and rather high. Figured from the type, no. 60463 

 A. N. S. 



It varies in degree of inflation, as the figures show. Dr. 

 Clapp has noted that the specimens from Evergreen, Alabama, 

 are nearly smooth, showing only obsolete striation. One meas- 

 ures 1.45 x 0.8 mm. The Texan form is also nearly smooth, 

 1.7 x 9 mm., and some have a thin palatal callus. All of the 

 localities given are for specimens in coll. A. N. S. 



It is an isolated species, without near relatives in our fauna. 



Subgenus ANGUSTULA Sterki. 



Angustula STERKI, Proc. U. S. Nat. Mus. xi, 1888, p. 378, 

 for V. milium and V. venetzii; Nachrbl. d. m. Ges. 1889, p. 

 P. & V., Proc. A. N. S. Phila. 1900, p. 597. 



