98 GASTROCOPTA, SOUTH AMERICA. 



Baur on bones of turtles, in southern Albemarle, are 2.3 mm. 

 long, 1.1 to 1.2 mm. diameter. The smallest seen from Albe- 

 marle (Iguana Cove) is 2.2 mm. long, others of the usual size 

 occurring in the same lot; the colors being from cartridge- 

 buff with white lip to tawny with cinnamon lip. One excep- 

 tionally simplified shell from this locality (pi. 19, fig. 10) has 

 neither infraparietal or interpalatal teeth, and the basal fold 

 is very minute. In most lots from Albemarle the shape varies 

 from somewhat ovate to cylindric. 



On Narborough Island (Snodgrass) the infrapalatal nodule 

 is generally either very low or entirely wanting, an inter- 

 palatal plica is usually absent, and the basal fold is very 

 small. The shape and thickened peristorne remain typical 

 (pi. 19, fig. 11). There appears, therefore, to be slight racial 

 divergence, since the form prevalent on Narborough is quite 

 rare among specimens seen from Albemarle. 



On Charles Island only specimens of medium and small 

 size have been found, length 2 to 2.4 mm. The crest behind 

 the lip is wanting in many examples, and not strongly devel- 

 oped in others. The teeth vary as in Albemarle examples. 



Tower Island has shells very similar to the narrower ex- 

 amples from Albemarle, and showing the same variations. 



This species, which seems to be rather common on several 

 islands of the Galapagos group, was first described by Profes- 

 sor Boettger as Pupa pfeifferi, said to be from Pitcairn Island, 

 from specimens supplied by Mr. Cuming. Nothing similar 

 to it has been found in Polynesia, and as Cuming collected 

 extensively in the Galapagos, there can be little doubt that 

 his locality was erroneous in this case, as in many others. 

 The original description of P. pfeifferi and copies of the 

 figures follow. 



Pupa pfeifferi Boettg. PL 19, figs. 4, 5. Shell related to 

 P. pediculus, but smaller, narrower, more oblong, pale cor- 

 neous-yellow, not whitish-pellucid ; whorls less convex. Aper- 

 ture smaller, rotund-quadrate, six-toothed, the teeth less 

 strong; one lamelliform angular, which is rather distinctly 

 bifid in the middle; one columellar; four smaller receding 

 palatals, which are punctiform except the larger third one. 



