ACHATINELLnxaS. xxi 



whorl descending in front; peristome ex- 

 panded; no columellar lamella. 



Genus ARMSIA, p. 132. 

 c 1 . Embryonic whorls flattened. 



d. Planorboid; no columellar lamella; um- 

 bilicus very wide. 



Genus PLANAMASTBA, p. 129. 



d 1 . Biconvex, fragile, umbilicus moderate 



or small, contained 4 to 10 times in the 



diameter; columellar lamella more or 



less strongly developed. 



Genus PTERODISCUS, p. 118. 

 Shell globose-conic, ovate or columnar. 



c. Shell imperforate, columnar or oblong, rather 

 large (length 25 to 75 mm.), solid, with con- 

 vexly conic summit of flat whorls ; columellar 

 lamella small; usually dark-colored. 



Genus CABETJA, p. 100. 



c 1 . Shell umbilicate, perforate or closed, usually 

 ovate-conic, but varying from globose-conic to 

 turrited; usually dull-colored and dextral; 

 living on the ground. Genus AMASTEA, p. 133. 

 c 2 . Shell usually perforate, ovate or turrite, yel- 

 low, pink or whitish, sometimes uniform, but 

 usually with zigzag black stripes or dote; 

 columellar lamella strong. Living on plants, 

 never on the ground. 



Genus LAMINELLA, p. 323. 



Planamastra 

 Armiella | 



Kauaia Pterodiscus 



Paramastra A m a s t r e 1 1 a C yclamastr a Armsia 



Metamastra 



Leptach a tina 



Approximate Phylogeny of Genera and Subgenera of Amastrinae. 



