86 PARTULINA, LANAI. 



peristoine unexpanded, labiate within, the right margin some- 

 what straightened, columellar margin dilated, vaultingly re- 

 flexed. Length 18^, diam. 9, aperture 8x83^ mm. Sand- 

 wich Is. (Pfr.) . 



Dr. Newcornb and all more recent authors have agreed in 

 considering A. fulva a synonym of variabilis. Specimens 

 measure: Length 17 to 18, diam. 10, aperture 8.3 mm. The 

 lip-callus is white, or brown with a white lip-edge. The widest 

 specimens approach semicarinata, but none are so wide as that. 

 It is sometimes cream-white. 



Mr. Thaanum found P. variabilis lower, P. semicarinata^ 

 higher on the main ridge of Lanai. 



44a. Var. lactea Gulick) . PI. 22, figs. 15, 16. 



" Shell sinistral, perforate, acuminately ovate, solid, shin- 

 ing, finely striated, and microscopically very finely decus- 

 sated, color ivory white ; apex acute ; spire conical, with out- 

 lines slightly convex; suture rnarginate, slightly impressed; 

 whorls 6y 2 , flatly convex; columellar fold central, brown, 

 strong ; aperture oblique, sinuately oval, reddish brown 

 within ; peristome white, thickened within ; with external mar- 

 gin arcuate, slightly reflected anteriorly; columellar margin 

 dilated, slightly detached; parietal margin thin. Length 22, 

 breadth 11% ; length of body- whorl 15 mm. Weight 8 

 grains ' (Gulick). 



Lanai : S. T. Alexander, D. Thaanum. 



The shell is rather snow-white than ivory-white, the colu- 

 rnella brown, tip of the fold paler, lip-callus purple-brown, 

 interior lilac. The spire is straightly conic, whorls but very 

 slightly convex. It is minutely but constantly perforate. It 

 is a very beautiful shell, differing from the white form oc- 

 curring in some variabilis colonies by its darker aperture. In 

 a series of about fifty before me, all are sinistral. 



Length 18 to 19, diam. 10 mm. 



Length 16.8, diam. 9 mm. 



45. P. SEMICARINATA (Newcomb). PI. 21, figs. 1 to 4, 13, 15. 



" Shell dextrorsal, solid, ovate'ly-conical, longitudinally 



substriated ; whorls 5, flattened, margin-ate above the last, an- 



