20 AMASTRA. 



The rough surface, white lining, embryonic sculpture, and 

 the mode of agglutination, are all features which we think 

 indicate relationship to A. obesa. 



So far as known, Cyclamastras of the umbilicata series do 

 not agglutinate; but as nearly all of them are fossils, this 

 point is somewhat uncertain. At all events, the Mauian 

 A. morticina differs from A. metamorpha by its more ample 

 umbilicus, the conspicuous angularity of the aperture at the 

 foot of the columella, and by its stouter figure. 



Most adult shells are clean, but the immature stage is some- 

 times copiously loaded with dirt, the thickest accumulations 

 being at the periphery and around the lip. See figures 3 

 and 4. 



A. METAMORPHA DEBILIS P. & C., n. Subsp. PL 5, figS. 6, 7. 



Differs from the preceding by the absence of any white 

 lining of the interior, the shell being very thin, even fragile. 

 Exterior russet throughout. Columellar lamella smaller and 

 more oblique. Average contour more slender than in 

 metamorpha. 



Length 13.1, diam. 5.8 mm. ; 6% whorls. 



Length 12.1, diam. 5.7 mm.; 6% whorls. 



Length 11.5, diam. 5.25 mm. 



Olowalu Gulch, at a greater elevation than A. metamorpha, 

 D. Thaanum, July, 1913. 



This may prove specifically distinct, if intergrades with 

 metamorpha do not turn up ; yet the general resemblance of 

 the two forms is such that they may well be associated for 

 the present. 



Series of A. umbilicata. 



For the greater part, these were shells of the plains and 

 low elevations, down to near sea level. With the passing of 

 the low forests these Amastras have become extinct, with 

 few exceptions. 



A. HARTMANI 'Newc.' Hartman. PI. 2, figs. 19, 20. 



Vol. XXI, p. 160. Specimens in the Newcomb collection, 



