ACHATINELLA JUNCEA. 241 



columella, the fold of which is lilac. There is also an albino 

 form in the same colony, pure white throughout. Surface 

 glossy, similar to A. cast a. Whorls convex, the suture mar- 

 gined on the last whorl. Columellar fold spiral, not very 

 prominent. Peristome thin, acute. 



Length 14.2, diam. 8.6, aperture 7.2 mm. ; 5^ whorls. 



Length 14.8, diam. 9, aperture 7 mm. ; 5~y 2 whorls. 



Oahu: Kolokukahau peak, at the head of Waiau valley on 

 the Waimalu division ridge, elevation 1450 ft. (Irwin Spald- 

 ing, Margaret and L. A. Thurston). Cotypes in coll. A. N. 

 S. P. and Bishop Mus. ; also in the collections of Spalding 

 and Thurston. 



Margaret's Achatinella is a thinner, less solid shell than 

 A. casta, texture and coloration resembling A. juncea, which 

 differs by its lengthened, slender contour. It appears to be 

 closely related to juncea, but the habitats of the two are rather 

 widely separated and the forms seem sufficiently distinct. No 

 evidence that it actually inter grades with the polymorphic 

 A. casta has been seen in the collections examined, though 

 its color-pattern is much like one of the common casta pat- 

 terns. It is doubtless, like A. juncea, of common ancestry 

 with casta. 



A. c. margaretce was discovered by Miss Margaret Thurs- 

 ton in March, 1909. "Four visits have resulted in finding it 

 on only three lehua trees. ' It is a shell of the misty summits. 



21. A. JUNCEA Gulick. PL 42, figs. 11 to 14. 



"Shell sinistral, imperf orate, elongately and acuminately 

 ovate, thin, shining, finely striated, snow white ; apex some- 

 what acute ; spire convexly turrited ; suture margined, well 

 impressed; whorls 6, convex; columella white, with a light 

 twisted fold near the body whorl. Aperture oblique, oval, 

 white within ; peristome moderately thickened, with external 

 margin slightly expanded anteriorly, arcuate, acute ; colu- 

 mellar margin narrow, adnate ; parietal margin very thin. 



" Var. &. With two or three brown spiral bands" (Gulick). 



Length 16, diam. 8, length of aperture 7.1 mm. (type 

 specimen). 



