172 



TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Fig. 80. 



lamella, columellar margin scarcely reflected. Greater 

 diameter scarcely 3, lesser 2^ mill. ; height, 1 J mill. (Bland.) 



Zonites Lansingi, BLAND, Ann. Lye. Nat. Hist, of N. Y., 

 XI. 74, Fig. 1. 2 (1875). 



In damp moist places, among leaves. Astoria, Oregon, 

 in the Oregonian Region. 



The aspect of the upper surface of the shell is very like 

 that of Z. multidentatus (Binney). 



Mr. Bland places the species in Zonites, hut, owing to 

 the character of the jaw, I am inclined to consider it a M i- 

 crophysa. 



One specimen of Lansingi, appearing to have the ani- 

 mal within it, was crushed between two glass slides, en- 



Microphysa Lansingi. a bling me, without the use of potash, satisfactorily to 

 observe the jaw and teeth remaining uninjured in the 

 tissues of the animal. 



Jaw low, wide, slightly arcuate ; ends scarcely attenuated, blunt ; cutting 

 margin without median projection; anterior surface with 14 broad, unequal, 



Fig. 81. 



D 



Jaw and teeth of M. Lansing^. 



crowded, flat ribs, slightly denticulating either margin. The first impression 

 given by the jaw is that it bears narrow, separated ribs, as in Bulimulus, Cylin- 

 dre.l/a, etc. A more careful study of it, however, shows the ribs to be very 

 broad, crowded, flat, with narrow interstices between them. 



Lingual membrane with 17 1 17 teeth; 6 laterals. Centrals (Fig. B) 

 with the base of attachment longer than wide, the lower lateral angles ex- 

 panded ; upper margin broadly reflected ; reflection very short, tricuspi'd ; side 

 cusps decidedly developed, short, bearing distinct cutting points ; median cusp 

 long, slender, bulging at sides, reaching nearly to the lower edge of the base of 



