HYATT'S CLASSIFICATION, ETC. 365 



or Lanai. The patterns of color are primitive and Amastra- 

 like in the most primitive species of the group, L. gravida, 

 that occurs in the southern valleys of the eastern range, from 

 Waialae to Maldki, and reappear in the western hills in 

 Waianae, according to Cooke's collection. The aperture and 

 columella become darker in this form, but the pattern remains 

 similar. The primitive brown periostracum of L. gravida is 

 wanting- in some of its varieties, and in L. straminea, but 

 modifications are retained, and no reticulated or zigzag mark- 

 ings are present. The evidence of transition from gravida 

 to some species of Amastra, although less convincing than if 

 intermediate varieties had been actually found, is neverthe- 

 less, considering the Amastra-like characteristics of gravida, 

 sufficiently complete to indicate that Laminella originated 

 from some form of Amastra. There is only one species of 

 that genus, however, that approximates -closely in appear- 

 ance, and when this is compared it is seen to be obviously 

 different. This is A. grossa, in which some varieties are very 

 similar to L. gravida. The affinities of gravida are, however, 

 decidedly more with the turritella series, to which this species 

 belongs, than to any other. The form of the spire and gen- 

 eral aspect being much alike. 



There is a distinctly barred pattern in the young of L. 

 gravida, but this subsequently gives place to a uniform pat- 

 tern. The young of L. sanguinea are so similar to those of 

 L. venusta of Molokai that the latter must perhaps be con- 

 sidered a dwarfed descendant of sanguinea of Oahu. The 

 protoconchs in both of these species are of a dark color, and 

 the shape of the spire is peculiar on account of the closely 

 coiled and slender aspect of the younger or apical volutions, 

 as well as the barred and zigzag patterns. The dwarfish 

 species of Molokai are succeeded in West Maui by a shell, 

 L. picta, that runs close to venusta, but is considerably larger ; 

 and this is succeeded in East Maui by L. bulbosa, a larger but 

 closely allied species. The species of Lanai, L. tetrao, is 

 more closely allied to L. picta of W. Maui than to any other. 



The genus can in fact be divided into two sections, which 

 are in accord zoologically and zoogeographically : The first 



