Vol. II, Pt. I] DALL— GALAPAGOS PULMONATA 2>79 



7. Bulimulus (Naesiotus) adelphus, new species 

 Shell of the same general type as the preceding from which 



it is best distinguished by a differential diagnosis; it is of 

 a light or very pale yellowish brown with a paler peripheral 

 band, six whorls, retractively, closely, axially threaded, the 

 threads cut into granules by sharp spiral stride, the last half 

 of the last whorl irregularly corrugated; the axial perfora- 

 tion larger, the aperture subquadrate with continuous margin 

 thickened but not reflected, a large tubercle on the pillar, a 

 prominent one medially on the inside of the outer lip, a much 

 smaller one on the body deeper in the throat ; the axis is 

 simple, tubular and not twisted. Length of shell 14.5 ; of 

 last whorl 10.0 ; of aperture 5.5 ; diameter 9 mm. 



Found with the preceding species by Ochsner in the arid 

 zone. 



8. Bulimulus (Naesiotus) lycodus, new species 



Shell small, solid, subacute, white, or yellowish white, with 

 a rose pink or bluish apex and six rapidly enlarging whorls ; 

 upper whorls finely, retractively, axially, closely threaded, 

 with fine spiral striation, the suture appressed ; last whorl 

 very coarsely, irregularly corrugated and punctate; base 

 rounded with a narrow umbilical perforation ; aperture with 

 a thick continuous white margin slightly expanded but not 

 reflected ; the mesial thickening of the outer lip obsolete, per- 

 ceptible in only a few specimens ; pillar with a very anterior 

 strong anteriorly inclined tubercle, continued into the throat 

 as a diminishing ridge around the axis of the last whorl ; on 

 the body is a sharp prominent narrow tooth also prolonged 

 backward as a narrow ridge ; axis in the upper whorls very 

 slender and conspicuously twisted. Length of shell 11 ; of 

 last whorl 8 ; of aperture 4.5 ; diameter 8 mm. 



Found by Ochsner on Indefatigable Island on tree trunks 

 at 450 to 550 feet elevation. 



9. Bulimulus (Naesiotus) alethorhytidus, new species 



Shell small, resembling the preceding but with the promi- 

 nent characters exaggerated and the size much reduced ; 

 v/horls five, rapidly enlarging, nucleus sparsely transversely 

 minutely lamellose, dimpled, the first three whorls rather 



