1C6 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



W. G. Binney, L. & Fr.-W. Sh., I. 80, Fig. 140 (1869). — Gould and 



Binney, Inv. of Mass., ed. 2, 413 (1870). 

 Helix ruderata, Adams, Sill. Journ. [i], 40, 408, not Studer. 

 Helix Oronkheiti, Newcomb, Proc. Cal. Acad. Nat, Sci., III. 180 (1865). 

 Patula striatella, Mouse, Journ. Port! Soc, I. 21, Fig. 48, PI. II. Fig. 6; Pi. 



VIII. Fig. 49 (1S64). 

 Anguispira striatella, Thyon, Am. Journ. Conch., II. 262 (1866). 

 Patula Oronkheiti, Tkyon, Am. Journ. Conch., II. 263 (1866). 



This is a species of the Northern Region, being found through British 

 America, at Great Slave Lake, etc., Canada, New England, and extends to 

 Virginia and Kansas. It has also been found in Arizona, Hell Gate River, 

 Idaho, in the Central Province, and has been quoted from the Pacific Province. 

 It may therefore prove to be universally distributed. 



Jaw arcuate, ends attenuated ; anterior surface with converging stria?; con- 

 cave margin irregularly notched, no median projection (p. 154, Fig. 61). 



Lingual membrane with 100 rows of 16 — 1 — 16 teeth (Morse). The lingual 

 examined by me (PI. IV. Fig. B) has 20—1—20 teeth, with 8 perfect laterals. 

 Animal : head, neck, and eye-peduncles dusky ; foot white. 

 Genitalia unobserved. 



As regards P. Cronkheiti, I am not able to decide about its specific distinc- 

 tion from striatella. Specimens have been sent me under this name from Ouna- 

 laska, from Klamath Lake, and various localities in the Pacific and Central 

 Provinces, one of which is here figured. 



This species bears a very strong resemblance, in general aspect, 

 JjLJJ' to perspectiva, with the immature shells of which it is very com- 

 monly confounded. It needs some attention to separate the two ; 

 but when the present species is once noticed, it cannot fail to be 

 considered very distinct. Its discriminative characters, as com- 

 pared with the former species, are as follows : The mature shell 

 , . . is smaller, and has generally rather less, and never more than 4 

 whorls ; and in shells of the same size the number of volutions is 

 less. It is thinner and more delicate; its color is lighter; its stria? of increase 

 are more numerous, more oblique, much finer, and less prominent ; its suture 

 is less deeply impressed ; its spire is more convex, and its umbilicus less ex- 

 panded. The character of the epidermis is the same in both. The lustre of 

 the epidermis resembles that of satin. 



Whiteaves (Can. Nat., VIII. 56) says it has been suggested that striatella is 

 identical with 11. omphalos, Searles Wood, an Eocene fossil of Ileadon Hill, Isle 

 of Wight. 



Patula pauper, Gould. 



Shell small, discoidal, reddish horn-colored, with incremental ribs, below 

 chalky; whorls 4^, rather convex ; suture deep ; aperture very oblique, falling 

 forward. Diameter, ^; axis, -J poll. (Gould.) 



