1911.] NATURAL SCIENCES OF PHILADELPHIA. 587 



practically varices; the spiral strise show 

 strongly on the ribs; size, 7x2 mm., 



gray ana C. B. Ad. 



11. Labium slightly separated except at its upper 



extremity; 16 arcuate ribs per whorl; 



size, 9.7 x 2 mm striosa C. B. Ad. 



dd. Labium not detached from the penultimate whorl. 



12. Linguiform part much produced below, sub- 



acute; 36 ribs per whorl; length, 9.2 mm., 



gi'acilis var. parva C. B. Ad. 



13. Linguiform part excessively produced below; 



very narrow and subacute; length, 7.5 mm., 

 lypica var. pygmcea C. B. Ad. 



14. Labrum but little produced below, moderately 



thickened and refiexed, not separated from 

 labium by a sinus, whorls remaining five; 

 size, 4.1 x 1.3 mm. parvula? P. & B. 



15. Labrum rounded, not produced into a lingui- 



form portion, separated from the labium by 

 a sinus; size, 4.5 x 1 mm. pygmcea C. B. Ad. 



16. Labrum obtuse, expanded, rounded, 40-50 ribs 



per whorl, 36 spiral stria; on the penultimate 

 whorl; size, 4.1 x 1 .1 mm. microglypta P. & B. 

 B. Whorls with transverse (axial) ribs, but without microscopic 

 spiral strise. 

 a. Length of shell, 10 mm. or more. 



b. Labium separated by a groove or space from the penulti- 

 mate whorl. 



17. Labrum separated from labium by a sinus, refiexed and 



thickened, very much produced in the lower part; 

 size, 17 x 5 mm jamaicensis Pfr. 



18. Labium separated from the penultimate whorl except 



at its upper extremity. Linguiform part of labrum 

 at the anterior extremity of the right side, well pro- 

 duced obliquely, not narrow, subacute; ribs 35 per 

 whorl, prominent, acute-edged; size, 10 x 2 mm., 



media C. B. Ad. 



19. Labium thickened and separated from penultimate whorl. 



Linguiform part excessively produced obliquely down- 

 ward, narrow and acute; ribs 36 per whorl; size, 

 15 x 4.5 mm fortis C. B. Ad. 



20. Labium separated from the penultimate whorl; lingui- 



form part produced obliquely and laterally, wide, 

 obtuse; ribs 38 per whorl, slender and arcuate; size, 



16.5 x 4.75 mm. magna C. B. Ad. 



bb. Labium not separated from the penultimate whorl. 



7 This is the species described by Edward Chitty (Cord. Conch, of Edward 

 Chilly, No. 1, Kingston, Jamaica, 1853, p. 6) under the name Geomelania parva 

 Chitty. This name being preoccupied by G. gracilis parva C. B. Adams, we 

 would propose the name Geomelania parvula for Chitty's species. 



