ANTILLEAN OBELISCUS. 259 



Key to species of Stenoyyra. 



I. Rather large species, 28 to 50 mm. long, 7 to 14 mm. diam. 

 a. Surface without spiral striation; Cuban. 



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

 28 x 7 to 37 x 8 mm. 0. maximus, no. 18. 

 bb. 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. 



b. Length 45-48 mm., about 4 times the diam. 



0. salleanus, no. 27. 

 bb. Length 28-37 mm., 4!/o to 5 times the diam. 



0. s. disparilis, no. 27 a. 



bbb. 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. 



b. Weakly striate; sutures of embryonic whorls 

 crenulate ; 13.7 x 3.7 mm. with 8y 2 whorls. 



0. kendersoni, no. 24. 



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

 10 whorls. 0. simpsoni, no. 25. 



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

 convex. 



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

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



0. swiftianus, no. 26. 



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

 length, yellow, very obliquely striate; 20 to 

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

 whorls. 0. clavus, no. 23. 



bbb. 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. terebmster, no. 22. 



