VERTIGO. 217 



Moll., IV. 148; L. & Fr.-W. Sh., I. 253 (1869). — Morse, Amer. Nat,, I. 

 668, Figs. 57, 58 (1868). — Tryon, Amer. Journ. Conch., III. 310, 22 (1868). 

 — Gould and Binney, Inv., 442, Fig. 704 (1870). — Fischer and Crosse, 

 Moll. Mex. et Guat., 310 (1870). 

 Vertigo tridentata, Wolf, Am. Journ. Conch., V. 198, PI. XVII. Fig. 1. 

 Pupa ovata, Gould, Bost. Journ. Nat. Hist., IV. 350, PI. XVI. Figs. 7, 8 (1843). 

 — DeKay, N. Y. Moll., 50, PI. IV. Fig. 50 (1843). — Adams, Vermont Mol- 

 lusca, 157 (1842); Silliman's Journal [i], XL. 271. — Kuster, in Chemnitz, 

 ed. 2, 118, PI. XIV. Figs. 1, 2; XV. Figs. 35, 38. — Pfeiffer, Mon. Hel! 

 Viv., II. 360; Symbols, II. 54. 

 Pupa modcsta, Say, Long's Exped., II. 25, PI. XV. Fig. 5 (1824); ed. Binney, 



32, PI. LXXIV. Fig. 5. — Gould, Invertebrata, 188, Fig. 119 (1841). 

 Pupa ovulum, Pfeiffer, olim, Symbolae, I. 46. 



Isthmia ovata, Morse, Journ. Portl. Soc, I. 38, Fig. 93 ; PI. X. Fig. 94 (1864). 

 Over all the Eastern Province, having been found from Maine to Texas. 

 Also in the Central Province in Arizona. For its presence in Europe, see 

 Jensen, Bidr. til Kristianiafjorden Moll., 68, 80. Also quoted from Mexico 

 and Cuba. 



Jaw arcuate, of uniform breadth, ends square and horizontal ; anterior 

 surface with longitudinal wrinkles •, concave margin simple, with a median 

 projection. 



Fig. 122. 



Vertigo ovata. 



Lingual membrane with 90 rows of 29 teeth (14 — 1 — 14), 9 perfect laterals; 

 centrals and laterals triscuspid, marginals serrated. (Fig. 118, p. 213.) 



Head and back deep cherry-red, posterior part of foot bluish, base whitish. 

 Eye-peduncles larger towards the extremities, or remarkably club-shaped; ocular 

 points distinct. The anterior extremity of the foot is dilated and trilobate, the 

 middle lobe minute, lateral lobes rounded. Length rather greater than that of 

 the axis of the shell. 



Of forty specimens of this shell examined witli the aid of a microscope, one 



