ANTILLEAN OBELISCUS. 261 



Length 30.5, diarn. 7.8, aperture 8.1 mm.; whorls 101/2. 

 Length 32, diam. 7.8, aperture 7.6 mm. ; whorls 

 Length 28, diam. 7, aperture 7.1 mm.; whorls 

 The diameter of the apex at the second whorl is 1.7 mm. 

 There is also a thinner form, almost translucent, but other- 

 wise like the preceding, which has been noticed by Pfeiffer, 

 and figured (see fig. 5). It is found 'at Yateras. An em- 

 bryonic shell out of one o'f these is 3.5 mm. long with 3% 

 whorls, with the axis imperforate and the columella strongly 

 twisted spirally. 



The name S. gigas was nowhere defined by Poey, but 

 Pfeiffer applied it in the place of typical S. maxima, evi- 

 dently because the latter name was in use in Bulimus. 



Var. PRINCEPS Pilsbry. PI. 31, figs. 7 to 11. 



Shell imperforate, very solid, white under a yellowish (or 

 very thin pale greenish-yellow) cuticle; very weakly striate. 

 Spire regularly tapering from the last whorl to the upper 

 fourtJi, which is decidedly contracted; apex large and 

 rounded, the width at the second whorl being 2 mm. AVhorls 

 lO 1 /^, very slightly convex, slowly and regularly increasing in 

 length. Aperture moderately oblique, ovate, the columella 

 rather narrow, vertical and straight. 



Length 38, diam. 11, aperture 10.5 mm. Type. 



Length 38, diam. 10.2, aperture 10 mm.; whorls 11%. 



Length 35, diam. 9, aperture 9 mm. ; whorls lO 1 /?. 



Length 37, diam. 12, aperture 11 mm. ; whorls 10. 



Length 44, diam. 14 mm. (P/V., fig. 9). 



Length 30, diam. 9, aperture 8.5 mm. ; whorls 10. 



Eastern Cuba: Monte Libano, etc. 



Bulimus gigas Poey, var. g, PFR,, Novit. Conch., p. 372, 

 pi. 87, f. 1, 2. 



This form differs conspicuously from typical 0. rnaximus 

 by its larger size, more robust form and greater solidity ; yet 

 there is great variation in these characters, and some speci- 

 mens, such as that drawn in fig. 7, form a partial transit ion 

 between the smaller and larger forms. One old specimen in 

 the series of 16 before me has lost the apical whorls and 

 closed the breach by a plug. 



