6 Unizcrsity of Michigan 



(Pfeifferj from Guatemala. The longer and heavier forms 

 (true shiiftlcicorthi) certainly approach quite closely that spe- 

 cies. However, in all of the specimens that I have seen, S. 

 lattrci has the embryonic whorls smaller in proportion to the 

 size of the shell, so that the apex appears sharper than in S. 

 ii'rigua. Also, in the former, the suture is more deeply 

 impressed, and ,each whorl appears as if shoved up over the 

 preceding one, so that the embryonic whorls look as if they 

 had broken loose along the sutural attachment and slumped 

 down into the surrounding whorls. In addition, in the speci- 

 mens before me (A. X. S. P.), the columella is more nearly 

 truncate in lattrci than in iri'igua, although the descriptions of 

 differen'; authors disagree on this point. I have not seen speci- 

 mens of Stvcptostyla quirozi Strebel (1878), but, from the 

 description and figures, it appears to be more closely related 

 to S. slrcptostyla (Pfr.) or cyliiidracca (Fir.), which com- 

 prise a divergent otTshoot from the same lattrci stock. 



]\ly specimens belong to the form si in His, as used here. 

 They all show some signs of spiral sculpture, but two have the 

 vertical, impressed lines especially well-marked near the aper- 

 ture, so as to approach typical similis of Strel)el. Two others 

 slightlv approach typical irrigiia, in that the vertical lines are 

 accentuated near the su'ure. All are rather small and thin- 

 shelled, and have very faint, wavy varices of darker fulvous 

 on the light amber, general color. The whorls appear to have 

 a sutural Ijorder, but the lens shows this is simply due to the 

 transparency of the shell. The largest has a trifle over 6 

 whorls ; it measures : 



Altitude Greatest diameter Height aperture Diameter aperture 



21.5mm. 42 (9mm.) 77 (16.5 mm.) 19 (4mm.) 



SalasicUa margaritacca fPfeiffer) (1857). Four specimens 



(3 adult) ; from among leaves and humus on ground in low- 



