ANTILLEAN OBELJSCUS. 259 



Key to species of Stenogyra. 



I. Rather large specie's, 28 to 50 mm. long, 7 to 14 mm. diam. 

 a. Surface without spiral striation; Cuban. 



5. Diam. contained 4 to 4% times in length; 

 28x7 to 37x8 mm. 0. maximus, no. 18. 

 55. Diam. more than one-fourth the length; very 

 solid, the spire contracted above; larger. 



0. m. princeps, no. 18 a. 



aa. Surface with delicate spirals; cuticle yellow, some- 

 what lamellose in perfect shells; Haiti. 



5. Length 45-48 man., about 4 times the diam. 



0. salleanus, no. 27. 

 55. Length 28-37 mm., 41/2 to 5 times the diam. 



0. s. disparilis, no. 27 a. 



555. Wider, length 39, diam. 11 mm.; Mexico(?). 



0. rangianus, no. 28. 

 II. Smaller forms, less than 25 mm. long, or 6 mm. diam. 



a. Whorls all very convex ; small, pale and thin shells. 

 Haiti. 



5. Weakly striate; sutures of embryonic whorls 

 crenulate ; 13.7 x 3.7 mm. with Sy 2 whorls. 



0. hendersoni, no. 24. 



55. Finely, distinctly striate; 11.2x3 mm. with 

 10 whorls. 0. simpsoni, no. 25. 



aa. Later whorls more or less flattened, the earlier more 

 convex. 



5. Pellucid, glossy, small and very slender, 7x2 

 to 10 x 2.3 mm. with 7 to 9 whorls. 



0. swiftianus, no. 26. 



55. Very narrow, diam. contained 5 or 6 times in 

 length, ydllow, very obliquely striate; 20 to 

 24 mm. long, about 4 wide, -with 10% to 12 

 whorls. 0. clavus, no. 23. 



555. Wider species, diam. 4 to 4% times in length, 

 c. Yellowish ; 23 x 5 to 24 x 5.5 mm., aper- 

 ture 6 mm., with 9% to 10 whorls. Porto 

 Rico. 0. terebraster, no. 22. 



