428 A MANUAL OF AMERICAN LAND SHELLS. 



Soidelli,* and Lebmann. TLc jaw is low, wide, arcuate, with delicate 

 vertical stride. The lingual membrane (Lehmann, Lebeuden Schueeken, 

 p. 128, Plate XIII, Fig. 43) has 120 rows of 11-1-11 teeth each. The 

 centrals are small, tricuspid (Sordelli); the laterals, G in number, are 

 larger, and have a more highlj' developed reflection, and are also dis- 

 tinctly tricuspid ; marginals subquadrate, with a broad reflection, bear- 

 ing delicate denticles. 



I have examined the jaw and lingual dentition of C. Gundlachi, which, 

 for the sake of comparison, I repeat here : 



Jaw low, wide, slightly arciate, ends attenuated; whole surface 

 covered with about 22 crowded, broad, flat ribs, denticulatiug either 

 margin. 



Lingual membrane long and narrow. Teeth 18-1-18, with 4 perfect 

 laterals. Centrals with their base of attachment long, narrow, their 

 reflected portion about one-half the length of the base of attachment, 

 tricuspid; the middle cusp stout, with a short, blunt cutting point; 

 side cusps subobsolete, but with small, distinct cutting points. Lateral 

 teeth with their base of attachment subquadrate, much longer and 

 very much broader than that of the centrals, the reflected portion short, 

 stout, tricuspid ; the middle cusp very stout and long, reaching the 

 lower edge of the base of attachment, beyond which projects the short, 

 stout cutting point : side cusps subobsolete, but bearing distinct, 

 though small cutting points. There are 4 perfect laterals, the fifth 

 tooth being a transition to tbe marginals, by the base of attachment 

 being lower, wider, not exceeding the reflected portion, with one inner 

 large cusp, bearing one outer large cutting point, representing the outer 

 cutting point of the first four lateral teeth, and one inner, still larger 

 cutting j)oint, representing the middle cutting point of the first four 

 laterals, and one smaller outer cusp, bearing one small, sharp, bifid 

 cutting point, representing the outer side cutting point of the first four 

 laterals. The sixth tooth has the largest cutting point bitid. The 

 balance of the teeth are true marginals. They are very low, wide, with 

 two low, wide cusps, bearing each several irregular, blunt cutting j^oints. 

 The dentition of tbis species is, as would be anticipated, of the same 

 type as the allied Cwcilianella ocicula, as figured by Lehmann, Lebenden 

 Scbnecken Stettins, p. 128, Plate XIII, Pig. 43, and Sordelli, /. c, Fig. 



* Sordelli (Attl deila Soc. Italiaua di Sc. Nat., XIII, fasc. 1, p. 50, Plate I, Fij?. 25) 

 describes the ribs to be not straight, but curving, with a median point projecting 

 toward the (snd of the jaw, so that each rib resembles quite exactly the sign called 

 " brace " by printers. 



