XIV CLASSIFICATION. 



Key to Genera and Sections of Achatinellida. 



a. Columella straight or only weakly folded. 



6. Shell slender, turrite, usually sculptured; 3% em- 

 bryonic whorls, having coarse spirals, the last obli- 

 quely striped. NEWCOMBIA, p. 1. 

 6 1 . Shell oblong or ovate. 



c. Shell striped or tessellated, sometimes banded, 

 small, usually less than 17 mm. long. 



Perdicella, p. 15. 



c. 1 Shell zigzag striped, banded or white, usually 

 well over 17 mm. long, or if so small, the last 

 whorl is unusually large. Baldivinia, p. 90. 

 a 1 . Columella strongly folded. 



6. Shell dull or polished, usually with distinct spiral 

 striation ; the embryonic shell biconic, often striped ; 

 usually two or several embryos in the uterus at one 

 time. PARTULINA, p. 14. 



c. Shell small, tessellated or striped, columellar 

 fold thin. Perdicella, p. 15. 



c 1 . Shell larger, spirally striate, columellar fold 

 stout. Partulina, s. str., p. 23. 



c 2 . Shell polished, often banded, columellar fold 

 stout. Eburnella, p. 67. 



6 1 . Shell polished; spiral striation weak or almost want- 

 ing; embryonic shell short and broad, its last whorl 

 never striped obliquely; only one well-developed 

 embryo in the uterus at a time. Oahu : 



ACHATINELLA, p. 117.. 



c. Outer lip thickened by an internal callous 

 ridge ; shape oblong-conic or ovate, summit 

 obtuse. Bulimella, p. 118. 



c 1 . Outer lip but little or not thickened within, 

 not expanded; summit conic, the embryonic 

 whorls not conspicuously flattened. 



Achatinellastrum, p. 180. 



c a . Outer lip thickened within ; shape globose- 

 conic ; embryonic whorls almost flat. 



Achatinella, s. sir., p. 274. 



