COSTIGO. 367 



apex rather acute. Whorls 5, convex, separated by a deep 

 suture, very densely obliquely striatulate and ornamented 

 with distant hair-like riblets, the last whorl somewhat en- 

 larged, rounded basally, % the height of the shell, more 

 strongly ribbed towards the aperture, and not ascending. 

 Aperture ample, nearly vertical, semioval, slightly angular at 

 the sinulus, 4-toothed, the teeth compressed; 1 parietal, 

 simple, oblique, strong; 1 columellar, horizontal, in the 

 middle of the columella; palatals either 2, widely separated, 

 the lower one stronger, or only a lower fold. Peristome ob- 

 tuse, narrowly expanded, colored like the outside, the mar- 

 gins joined by a light callus, columellar margin somewhat 

 dilated. 



Length 1.75 to 2, diam. 1.125 to 1.25, alt. and width aper- 

 ture 0.75mm. (Bttg.). 



Moluccas: Sirisori on Saparua Island (Strubell). 



Vertigo (Costigo) sa^aruana BTTG., Bericht Senck. naturf. 

 Ges., 1891, p. 270, pi. 3, f. 12, 12a. 



Distinguished from the externally similar genus Leuco- 

 chttus by the single, entirely simple parietal tooth, from the 

 oceanic Vertigine group Ptychochilus, which otherwise is very 

 closely related, by the absolute lack of an angular tooth. 



2. COSTIGO CALAMIANICA (Moellendorff). Not figured. 



Vertigo calamianica Mlldff., from Busuanga, is mentioned 

 as a new species of the section Costigo in von Moellendorff 's 

 Verzeichnis, Abhandl. Nat. Ges. Gorlitz, xxii, 1898, p. 152. 

 It is evidently the form alluded to by Boettger, following his 

 account of C. saparuana, in the following terms: "A second 

 species of Costigo lives on Busuanga, Catanduanes, Philip- 

 pines ; it is a new species, for which I am indebted to Consul 

 Dr. O. Fr. von Moellendorff, and which has no cuticular ribs 

 in addition to the sharp striation, and in which palatal teeth 

 are lacking." 



3. COSTIGO BORBONICA (H. Adams). PL 33, fig. 7. 



Shell deeply rimate, oblong-ovate, thin, nearly smooth, 

 silky, rufous-brown. Spire convexly conic, the apex obtuse, 



