UNIVERSALLY DISTRIBUTED SPECIES. 61 



Zonitcs arborcus. Say. 



Shell umbilicated, depressed, very slightly convex, thin, pellucid; 

 ei)idermis amber-colored, smooth, shining; whorls 4-5, with fig. 13. 

 very minute, oblique strioe, apparent when viewed with the 

 microscope; aperture transversely rounded; peristome thin, 

 acute ; umbilical region indented ; umbilicus moderate, well 

 developed, round, and deep. Greater diameter 5, lesser 



4^™" ; height, 2f '"". Z. arboreus. 



Helix arhorea, Say, Nich. Encyc, pi. iv, fig. 4; Bixxey's ed. T), pi. Ixxii, fig. 5 (1816, 

 1818, 1819).— Eatox, Zool. Text- book, 193 (1826).— Binney, Bost. Journ. Nat. 

 Hist., iii, 42-2, pi, xxii, fig. 1 (1840); Terr. Moll., ii, 235, pi. xxix, fig. 3.— De 

 Kay, N. Y. Moll., 30, pi. ii, fig. 10 (1843).— Gould, luvertebrata, 182, fig. 110 

 (1841).— Adams, Veriuout Mollusca, 160 (1842).— Pfeiffer, Mou. Hel. Viv., 



1, 95.— Chemxitz, 2d ed., ii., 114, Tab. Ixxxv, figs. 33-35.— Reeve, Con. Icon., 

 733.— W. G. BixxEY, Terr. Moll., iv, 116.— Morse, Amer. Nat., i, 542, fig. 30 

 (1867). 



Helix Ottonis, Pfeiffer, olim, Weigm. Arch., 1840, i, 251. — Bixxey, Terr. Moll., ii. 



238, pi. xxix a, fig. 3.— W. G. Binxey, T. M., iv, 117. 

 Hyalina arhorea, Morse, Jonrn. Portl. Soc.,i, 14, fig. 28, pi. vi, fig. 29 (1864).— Tryox, 



Amer. Jonrn. Couch., ii, 251 (1866). — Gould and Bixxey, Inv. of Mass., ed. 



2, 396 (1870).— W. G. Bixxey, L. & Fr.-W. Sh., i, 33 (1869). 

 Hyalina Otfonis, Tryox, Amer. Journ. Conch., ii, 251 (1866). 



Helix Breiveri, Newcomb, Proc. Cal. Acad. Nat. Sci., iii, 118 (1864). 



Hyalina Breweri, Tryox, Amer. Jonrn. Conch., ii, 250, pi. iv, fig. 27 (1866).— W. G. 



Bixxey, L. & Fr.-W. Sh., i, 43, p. 66 (1869). 

 Zonites arboreus, W. G. B., T. M. U. S., v, 114. 



From Labrador to Texas, and on the Rio Chama, and Fort Wiugate, 

 in New Mexico ; from Florida to Great Slave Lake; also in Washoe 

 County, Nevada; in Montana; the Pacific Province from British Co- 

 lumbia to San Diego along the Coast Range. It may thus be said to 

 inhabit all North America. It is also said to be found in Cuba; also 

 in Guadeloupe. 



Jaw arcuate, narrow, with cur\ing, pointed ends; lower margin 

 smooth, with a wide median projection; uj^per margin with a corre- 

 sponding depression. 



Lingual membrane with 82 rows of 21-1-21 teeth (Morse). My speci- 

 men (T. M., V, Plate III, Fig. F) has about 16-1-16, with 5 perfect 

 laterals. There are distinct side cusps as well as cutting points to the 

 central and lateral teeth. 



Animal: head, neck, and eye-peduncles blackish or indigo blue; up- 

 per parts bluish ; posterior whitish, transparent, sometimes wholly 

 white. Foot thin and narrow. It has the longitudinal furrows, but 

 on account of the transparent tissue of the foot, I find it difQcult to dis- 

 tinguish any caudal pore. 



