YUIA'AKTA. 57 



M. FUSINA, Dall. 



Shell ovate-fusiform, with the spire nearly as long as the 

 aperture, polished waxen white, five-whorled ; whorls of the 

 spire well marked and rotundate though covered with a trans- 

 parent glaze ; suture distinct ; apex rounded ; lines of growth 

 perceptible under the glaze, especially near the suture on the 

 last whorl ; aperture short, lunate, with no posterior angle in 

 the outer lip, which gently rounds to the body-whorl before and 

 behind ; outer lip a little thickened inside, simple, not reflected ; 

 folds four, the two anterior ones very oblique and close together ; 

 canal not flaring, short, and not twisted backward. Long, of 

 shell, 8-0 ; of last whorl, 6*0 ; of aperture, 4'5. Max. lat., 4*0 ; 



lat. of aperture, 1-5 mm. 



Yucatan Strait, 640 fms. 



This has somewhat the shape of Marginella nodata, in a gen- 

 eral way, but is more evenly fusiform, and quite peculiar in its 

 even taper, which does not seem to be ascribed to any other 

 species (Dall). 



M. SEMINULA, Dall. 



This species differs from the last by its proportionally shorter 

 spire containing one less whorl ; by the less distinctly marked 

 suture ; by the shouldering of the last whorl which angulates 

 the outer lip in adult specimens, the lip in this vicinity being 

 generally much thickened and slightly reflected, somewhat pro- 

 duced in the middle, and thinning towards the distinctly flaring 

 canal ; the columellar folds are more evenly separated and the 

 canal is slightly recurved. In other respects it resembles M. 

 fusina. Long, of shell, 7*0 ; of last whorl, 5*62 ; of aperture, 

 5'12. Lat. of shell, 3*5 ; of aperture, 1'25 mm. 



Yucatan Strait, 640 fms. 



There is some variation in size and in the way in which the 

 outer lip is thickened in different individuals. The shape is not 

 far. from that of M.f estiva. The measurements are of the largest 

 of several specimens (Dall). 



M. YUCATECANA, Dall. 



Shell with three and a half to four whorls, smaller than the 

 last and the adult specimens proportionally more slender and of a 



