STREPTOSTYLA. 145 



where one whorl joins another, visible by transparence 

 through the whorl from the outside, a subsutural band is 

 formed. This varies in width in the different species, and is 

 often a valuable distinctive character. Many of the species 

 are very similar and their identification is often a matter of 

 extreme difficulty. Of all authors who have discussed them, 

 Strebel's work is the most thorough in description and illus- 

 tration. The following account is supplemental to that in 

 Vol. I. 



Streptostyla flucki Bartsch, Nautilus, xx, p. 4, from near 

 Wani, Nicaragua, has not been described. 



Subgenus STREPTOSTYLA s. str. 



The shell is large, oblong and striate, with costulate em- 

 bryonic whorls, only the first half whorl or less being nearly 

 smooth. Aperture long and narrow, the columella twisted in 

 a strong, calloused spiral fold. Type S. nicoleti. 



1. S. NICOLETI (Shuttleworth). Vol. I, p. 43. 



Subgenus CHERSOMITRA v. Martens. 



Chersomitra MARTS., in Albers, Die Heliceen, 1860, p. 33, 

 type S. nigricans. 



The shell is smooth or finely striate above, with a varnish- 

 like gloss, the embryonic whorls smooth, apex rounded. The 

 aperture is long and narrow, pirif orm or lanceolate ; colu- 

 mella with a more or less convex and calloused spiral fold. 

 Type 8. nigricans. 



2. S. NIGRICANS (Pfr.). Vol. I, p. 45. 



3. S. MITR^FORMIS (Shuttlew.). Vol. I, p. 45. 



4. S. LATTREI (Pfr.). Vol. I, p. 44 (as 8. delattrei Pfr. 



Glandina oliva Morelet, Testae. Noviss., i, p. 13, is a 



synonym). 



4a. S. LATTREI var. EDWARDSIANA C. & F. Vol. I, p. 45. 

 46. S. LATTREI var. SALLEI C. & F. Vol. I, p. 44. (Var. 



"sallcei" Martens.) 



5. S. IRRIGUA (Shuttl.). Vol. I, p. 46. 



