122 



TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Fig. 39. 



. conspectus, 

 enlarged. 



equal to two sevenths the diameter of the shell ; aperture ob- 

 lique, roundly lunate ; peristome simple, straight, the margins 

 approaching, the columellar margin scarcely dilated. Greater 

 diameter 2, lesser If mill.; height, 1 mill. 



Helix conspecta, BLAND, Ann. N. Y. Lye. VIII. 163, Fig. 7 



(Nov. 1865). 

 Pseudohyalina conspecta, TRYON, Amer. Journ. Conch., II. 265 



(1866). 

 Hyalina conspecta, "W. G. BINNEY, L. F& Fr.-W. Sh., I. 41 



(1869). 



In the Pacific Province at San Francisco and Monterey, 

 California. In the Central Province at Cunningham Gulch, Colorado. 



Z. conspectus differs from Patula asteriscus in having an elevated spire and a 

 smaller umbilicus. The rib-like striae are more numerous, but scarcely raised 

 above the surface of the shell, which, under the microscope, is very similar to 

 that of H. asteriscus. Z. exiguus also has very prominent ribs, but they are 

 independent of the striae of growth and run obliquely to them. 



Animal not observed. 



Zonites exiguus, STIMPSON. 



Shell broadly umbilicated, depressed, pellucid, greenish horn-color, marked 

 with delicate revolving lines, and distant longitudinal ribs obliquely decus- 

 sating the incremental strias ; spire scarcely elevated, apex 

 free from strias ; whorls 3j, convex, the last rounded, widely 

 umbilicated below; aperture oblique, transversely rounded, 

 remote from the axis ; peristome simple, acute, its columellar 

 extremity not reflected. Greater diameter, 2^ mill. ; height, 

 mill. 



Fig. 40. 



2.. exiguus, 

 enlarged. 



Helix exigua, STIMPSON, Proc. Bost. Soc., III. 175 (1850). GOULD, T. M., III. 



16. W. G. BINNEY, T. M., IV. 102, PI. LXXVII. Fig. 19. PFEIFFER, 



Mon. Hel. Viv., III. 102. MORSE, Amer. Nat., I. 543, Fig. 34 (1867). 

 Helix annulata, CASE in Sill. Journ. [2] 1847, III. 101, Figs. 1-3; Aim. and 



Mag. Nat. Hist. 1847, 338, preocc. 1 PFEIFFER, Mon., III. 103. 

 Helix striatella, junior, teste GOULD, Sill. Journ., III. 276 (1847). 

 Pseudohyalina exigua, MORSE, Journ. Portl. Soc., I. 16, PI. II. Fig. 8 ; PI. 



VII. Fig. 33 (1864). TKYON, Amer. Journ. Conch., II. 265, PI. IV. Fig. 57 



(1866). 

 Hyalina exigua, W. G. BINNEY, L. & Fr.-W. Sh., I. 42 (1869). GOULD and 



BINNEY, Inv. of Mass., ed. 2, 400 (1870). 



A species of the Northern Region, noticed hitherto in Canada, New York, 

 and New England ; Tawas Bay, Michigan. 



1 This name is preoccupied in Helix, not in Zonites, and should be adopted, according 

 to the strict laws of nomenclature. 



