212 



PROCEEDINGS OF THE ACADEMY OF 



Alabama, Dr. E. R. Showalter (pi. XII., fig. 3). There are 

 25 1 25 teeth, with 10 perfect laterals. 



Helix jejuna, not examined. 



Helix devia (pi. XII., fig. 4) has 23123, with 16 perfect 

 laterals. 



Helix profunda (pi. XII., fig. 5) has 40 1 40 teeth, with 

 about 14 perfect laterals. 



Helix Sayii (pi. XL, fig. 5) has 42 1 42 teeth, with about 15 

 perfect laterals. 



Fig. 53. 



Subgenus Acanthinula. 



We have but one species within our limits, H. harpa, whose 

 jaw and lingual dentition have been described and figured by 

 Morse. Judging from his figure (fig. 53) and text, 

 the anterior surface of the jaw seems to have sub- 

 obsolete ribs which mark the lower margin ; it is 

 low, wide, strongly arched, with blunt, scarcely 

 attenuated ends ; cutting edge with a wide and 

 very slightly produced, broad median projection ; 

 transversely and longitudinally striate. 



Lingual membrane long and narrow, 120 rows of 17 1 17 

 teeth, with 6 perfect laterals. The centrals have a square base of 



Jaw of 

 Helix harpa. 



[Morse.] 



Fisr. 54. 



Lingual dentition of Helix harpa. [Mor6e.] 



attachment, the upper margin squarety reflected ; the reflection is 

 very small, tricuspid, the side cusps very small, blunt, the median 

 cusps very long and narrow, not reaching the lower edge of the 

 base of attachment, not even with its short cutting point; side 

 cusps also, I presume, with cutting points, though none are shown 

 in Morse's figure. Laterals like the centrals, but unsymmetrical 

 by the suppression of the inner side cusps, and cutting points. 



