52 VARICELLA. 



a 1 . Ribs Tin-armed 1 , 13 to 15 on last whorl, intervals with 

 18-20 'fine striae and spiral lines ; reddish-brown, not 

 streaked ; 12 x 3 mm. with 9 whorls ; W. Cuba. 



V. pichardi, no. 2, 



II. Surface not spirally striate, though sometimes the longi- 

 tudinal striae are a little waved ; corneous or pale brown, 

 not streaked. 



a. East Cuban forms. 



&. 14 low 'compressed ribs on last whorl ; 6 x 1.75 



mm. with 8 whorls. V. scalarina, no. 5. 



ft 1 . Elevated, cord-like ribs; 9.5 x 2 mm., with 10 



whorls. V. multicosta, no. 7. 



a 1 . Middle and west Cuban forms, etc. ; icolumella not 



truncate or very indistinctly so. 



ft. Axis gyrate, a central false umbilicus visible 

 from the base; very slender, 6 x 1.6 to 7 x 1.75 

 mm., 7 or 8 whorls. 



c. About 20 ribs on last whorl, 4 to 5 striae 

 in eaich interval. V. gracillima, no. 3. 



c 1 . 9 to 12 striae in each interval. 



V. g. sanctithomensis, no. 3&. 

 c 2 . About 25 ribs on last whorl, 6 to 8 striae 

 in each interval. 



y. g. floridana, no. 3a. 



ft 1 . Axis straight, no 'central hole visible ifrom the 

 base; shell less slender, diam. 2 mm. or more, 

 c. 20 to 21 smooth ribs on last whorl, 8 to 11 

 striae in each interval ; 8 to 9.5 mm. long. 



V. manzanillensis, no. 4. 



c 1 . 16 to 18 ribs on last whorl, 10 striae in each 

 interval; 6 to 7 mm. long. 



V. m. cienfuegosensis, no. 4Z>. 



c 2 . 24 to 29 ill-developed ribs on last whorl, 



5 to 7 striae in each interval, 8 to 9 mm. 



long. V. m. trinitatis, no. 4a. 



1. V. ACUTICOSTATA (Orbigny). PI. 15, figs. 1, 10. 



Shell tapering, turrite, attenuate near the summit, thin,. 



