PACIFIC COAST SPECIES. 115 



curved and turning upward at a rather sharp angle; peristome incum- 

 bent, with a deep stricture behind it, moderately rellexed, roseate; on 

 the parietal wall of the aperture is a distinct, oblong, erect, white tooth, 

 not connected with either extremity of the peristome. Greater dia- 

 meter, 7^°"™ ; height, 5°>™. 



Helix germana, GOVLX), U. S. Expl.Exped. Moll. (1852), 70, fig. 40, a,b,c; Terr. Moll., 

 ii, 156, pi. xl, a, tig. 3.— Pfeiffer, Mon. Hel. Viv., iii, 269.— W. G. BlNNEV, 

 Terr. Moll. U. S.,iv, 11 ; L. & Fr.-W. Sli., i, 120 (1869). 



Stenotrema germana, Tryon, Am. Journ. Conch., iii, 58 (1867). Sienotrema gervianum, 

 W. G. BiNNEY, Terr. Moll., v, 300. 



Oregonian Eegion, at Astoria. 



Jaw more resembling the type usual in the subgenus Stenotrema than 

 MesodoHj the ribs, 11 in number, being broad and crowded. There are 

 forms of germanum closely connecting the species with Mesodon Colum- 

 hianuSj Lea. I have, while treating the latter species (see below), 

 pointed out the decided specific differences shown in the jaw and geni- 

 talia; at the same time I have stated that, by the want of the internal 

 tubercle, germanum is more nearly allied to Mesodon than to Stenotrema. 



S. germanum (Terr. Moll., Y, Plate VII, Fig. G) has 28-1-28 teeth, 12 

 perfect laterals. The left-hand figure shows one of the few marginals 

 which have the outer cusp bifid. 



Very much larger specimens than that figured are fouud, formiug a 

 series of size to Mesodon Columbianus. 



TRIODOPSIS. (See below.) 



Triodopsis loricata, Gould. , 



Shell umbilicated, depressed, spire less convex than the base, thin, 

 of a yellowish-green color, having the surface everywhere ornamented 

 with small, crescent-formed scales of the epidermis, in relief, arranged 

 along the lines of growth and in quincunx ; whorls 5^, slightly convex, 

 separated by a deeply impressed suture, and forming a low, conical 

 spire ; the periphery of the last whorl is slightly angular near fig. 83. 

 its posterior jiortion ; the base is rounded, tending rapidly to a 

 deep, umbilical depression, with a small perforation ; aperture 

 small, very oblique, crescentic, having a small, acute tooth on y.jowcata, 

 the right margin of the peristome, a transversely oblong one at enlarged. 

 basal margin, and a prominent, compressed, curved, nearly horizontal 

 one ou the parietal wall, thus giving a three lobed outline to the aper- 

 ture j peristome white, slightly reflected^ having a very profound con- 



