368 COSTIGO. 



suture impressed. Whorls 5, a little convex, the last some- 

 what compressed at base, swollen and pitted behind the aper- 

 ture. Aperture truncate-oval, subvertical, four-toothed : one 

 entering, compressed parietal tooth, one tooth deep on the 

 columella, two in the palate, the upper one minute. Peri- 

 stome a little expanded, white-lipped, the margins joined by 

 a thin callus, right margin somewhat sinuous. Length 2 1 /, 

 diam. 1% mm. (H. Ad.). 



Bourbon (G. Nevill). 



Vertigo (Alaea) borbonica H. AD., Proc. Zool. Soc. Lond., 

 1868, p. 290, pi. 28, fig. 8. 



4. COSTIGO DESMAZURESI (Crosse). PL 33, fig. 12. 



Shell umbilicate, shortly cylindric, thin, translucent, ap- 

 pearing smooth to the naked eye, but really marked with fine, 

 slightly oblique striae visible only under a lens. Shell a little 

 shining and of a light corneous-tawny color. Spire forming 

 a short cone terminating in an obtuse summit. Suture well 

 marked. Whorls 6, a little convex, the last whorl a little 

 smaller than the spire, slightly tapering and rounded at the 

 base. Aperture subvertical, of rounded semilunar shape and 

 provided with 2 unequal spiral lamellae [palatal folds| situ- 

 ated deep within. Peristome simple, narrowly expanded, a 

 little reflected, and of a light rosy white ; margins separated ; 

 parietal and columellar margins provided each with one in- 

 ternal tooth ; these two teeth being placed at right angles to 

 one another (Crosse). 



Length 2.25, diam. 1 mm. 



Rodriguez: Pointe aux Coraux (A. Desmazures). 



Pupa desmazuresi CROSSE, Journ. de Conchyl., xxi, 1873, 

 p. 140; xxii, 1874, p. 227, pi. 8, f. 3. 



Crosse remarks that one of the palatal folds is more readily 

 visible than the other, and it only is shown in the figure. 



5. COSTIGO NOBREI (Girard). PI. 34, fig. 10. 



Shell rimate, oval, very finely striate, as though vermie- 

 ulate, corneous, subtransparent. Whorls 4-41^, very convex, 

 with a deep suture, the last whorl contained about 2% time* 



