334 LAMINELLA, LANAI. 



Lanai (Newcomb) ; behind Koela (Perkins). 



Achatinella tetrao NEWC., Proc. Boston Soc. N. H., v. 1855, 

 p. 219; P. Z. S., 1854, p. 311 (animal) ; Ann. Lye. N. H. of 

 N. Y., vi, p. 334; Amer. Journ. of Conch., ii, p. 214, pi. 13, 

 figs. 11, 12 (shell). PFR., P. Z. S., 1855, p. 207 (1856); 

 Monogr., iv, 547. THWING, Occ. Pap. B. P. B. Mus., iii, p. 

 131, pi. 3, f. 1. Amastra (Laminella) tetrao SYKES, Fauna 

 Hawaiiensis, p. 352. Laminella tetrao Nc., GULICK, Evolu- 

 tion Racial and Habitudinal, 1905, p. 38, pi. 1, f. 8. 



The apex is somewhat more acute than usual. The first 

 half- whorl is smooth ; then weak longitudinal ribs begin, con- 

 tinuing for about two whorls; but in some shells they are 

 very weak, hardly noticeable as ribs. Subsequent whorls are 

 lusterless and marked with growth-lines only. The dark 

 markings often are visible in adults on the second whorl, 

 form a more or less dense network over the later whorls, and 

 on the last part of the last whorl they often become >coal- 

 escent into a nearly uniform blackness. The ground- color is 

 usually pale buff, the embryonic whorls, a band below the 

 suture and the columella rose, the interior more or less 

 roseate. Exceptionally the rose color is altogether wanting, 

 the apex yellowish, and the mouth white. Mr. Sykes notes 

 that in the series collected by Perkins the ground-color varies ; 

 " shades of crimson or rich orange predominate, but occa- 

 sionally the color is confined to a band below the suture, the 

 rest of the shell being whitish." The columellar lamella is 

 strong and less steeply ascending than usual in Laminella. 

 In one specimen two small folds were noticed above it. 



Length 17.2, diam. 11.2, aperture 8 mm. ; 6% whorls. 



Length 18.5, diam. 11, aperture 8 mm. ; 6% whorls. 



Length 17.2, diam. 10 mm. 



Length 14, diam. 9.5 mm. 



L. tetrao is closely related to the West Mauian L. picta, 

 from which it differs chiefly in the more copious marking, 

 producing a denser reticulation ; also in the prevalence of rose 

 color below the suture. 



Several embryonic shells washed out of one of the adult 

 shells figured, show that the coloration is greatly accelerated, 



