150 GASTROCOPTA, EAST INDIES, POLYNESIA. 



There is an average difference between Hawaiian and Poly- 

 nesian specimens, though individuals not distinguishable from 

 those of Oahu may be found in almost any large lot from the 

 southern islands. By the invariable reduction of the basal 

 fold, the Hawaiian race resembles the Philippine variety 

 closely. The occasional presence of an iuterpalatal plica I 

 have noticed also among pediculus from the Society Islands 

 and other places. Gould's original description follows. 



Vertigo nacca. Shell ovate, lucid, alabastrine, very deli- 

 cately striate. Whorls more than 4, ventricose ; apex obtuse ; 

 suture deep ; aperture subcircular, armed with a palatal tooth 

 (sometimes bifid), a eolumellar tooth, a basal tooth and a 

 labial tooth. Peristome strongly reflected, umbilicus rimate. 

 Axis V 10 , diam. V 12 inch. Hab. Hawaii, Dr. Neivcomb. The 

 denticles are similar to those of V. gouldii and V. tantilla. 

 The latter is smaller, has a rugose surface, and one more den- 

 ticle (Gould}. 



The original descriptions of species considered synonyms 

 of G. pediculus follow. 



Pupa artensis (pi. 25, figs. 5, 8, 14). Shell broadly umbili- 

 cate, cylindric-conic, of a corneous-white color, a little shin- 

 ing, transparent and smooth, but very fine, oblique, growth- 

 striae may be noticed. Spire conic, gradually tapering, com- 

 posed of 5 very convex whorls, separated by a deeply im- 

 pressed suture, the last whorl veutricose and compressed at 

 the base. Aperture somewhat rounded ; peristome thin, re- 

 flected ; the upper end of the right margin curved abruptly 

 towards the axis of the shell, to join the left margin, and 

 forming a continuous peristome. Interior provided with 5 

 teeth, one parietal, one columellar and three palatals; the 

 parietal, situated near the right side, is grooved above and 

 bifid at the point ; this formation is in consequence of its 

 being formed of two unequal teeth juxtaposed, the inner one 

 being more prominent. The columellar tooth is placed trans- 

 versely in the aperture, and perpendicular to the columella. 

 Of the three parietal [error for palatal] teeth, the point of 

 the upper one corresponds to the bifurcation of the parietal ; 

 the next one is almost directly opposite the internal portion 

 of the parietal ; while the third is in the middle of the space 

 between the columellar and second parietal [error for palatal]. 

 Of the 5 teeth, the parietal, columellar and second palatal 

 are the most prominent. Length 2, width 1 mm. 



