380 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



aperture lunate-orbicular, peristome patulous or straight, within labiate with 

 callus, the eolumellar margin reflected, generally callous. 



Found around the Mediterranean Sea ; a few species found elsewhere, 

 Mexico, Japan, etc. One species only introduced by commerce within our 

 limits. 



Jaw of our only species, P. aspersa, introduced by commerce at Charleston, 

 South Carolina (where it is still common), high, thick, arcuate; ends but little 

 attenuated, blunt ; cutting margin without median projection ; anterior surface 

 with 6 stout, separated ribs, deeply denticulating either margin (see Fig. 265). 



Lingual membrane of the same species (PI. X. Fig. D) long and narrow. 



Teeth 50 — 1 — 50, with 15 perfect laterals. Centrals with base of attachment 

 longer than wide, the lower lateral angles but slightly 



Fig. 265. ° n r> J 



produced, the lower margin in some cases with a 

 quadrate excavation or thinning as usually found in 

 Succinea; the upper margin broadly reflected, re- 

 flection very large, with a very stout, short median 

 cusp, bearing a short, stout cutting point reaching 

 the lower edge of the base of attachment ; side 



Jaw of P. aspersa. . 



cusps obsolete, but bearing well-developed, snort 

 side cutting points. Laterals like centrals, but asymmetrical by the suppres- 

 sion of the inner, lower, lateral angle of the base of attachment, and the inner 

 side cutting point. Transition teeth from the laterals to the marginals with 

 a more developed reflection, a shorter inner cusp bearing a greatly developed 

 bifid cutting point. Marginals low, wide, the reflection equalling the base 

 of attachment, and bearing one inner, long, oblique, acutely bifid cutting point, 

 and one shorter, outer, sometimes bifid, side cutting point. 



The only other Pomatia whose dentition has been figured is pomatia, which 

 shows the same type of teeth (Goldfuss, 1. c. PI. IV. Fig. 6), and Sieboldtiana, 

 Pfr. (see Proc. Am. Nat. Soc. Phila., 1875, PI. XXI. Fig. 8), which differs in 

 detail. The jaw of these and of numerous European species is known, and of 

 the same type as in aspersa. 



Pomatia aspersa, Muller. 



Shell imperforate, subglobose, rather thin, the surface rather coarsely and 

 irregularly striate, and finely wrinkled and indented ; the ground-color is yel- 

 lowish or grayish, with chestnut-colored bands of various width, across which 

 are narrow undulating flammules of yellowish ; the spire is rather obtuse, com- 

 posed of 4 or 5 moderately convex whorls, the principal one being very large 

 and ventricose ; the aperture is large, a little oblique, rounded lunate ; the 

 peristome white, sharp, turned slightly outward, and in the region of the um- 

 bilicus turning over the columella in a broad appressed callus, which is con- 

 tinued to the upper junction of the peristome. Greatest diameter, 32 mill. ; 

 height, 22 mill. 



