364 HYATT'S CLASSIFICATION, ETC. 



modified shells in the turritella subseries both in color pattern 

 and form, viz., A. cylindrica and its affines, occur at Waianae 

 on the western range, and that the second subseries must 

 have arisen from a modified descendant of turritella, A. 

 nigrolabris, that starts upon its career of evolution some- 

 where in or about the valley of Kalaikoa. This valley is the 

 next in succession going north to Waipio, which last marks 

 the northward extension of A. turritella, unless the Peck 

 collection is correct in carrying this species to Helemano. 



The reader will see at once that one cannot trace two sub- 

 series back into one radical species occurring in the south- 

 eastern valleys of the eastern range especially in a wave like 

 this, where other series have been traced, with abundant evi- 

 dence, in the opposite direction. 



The overlapping of turritella to the north to this extent, 

 if it were true, would, however, not invalidate the zoological 

 evidence. The conjunction of both subseries in the valleys 

 of the eastern range, and their continuation in the more modi- 

 fied forms of the Waianae range, can be accounted for only 

 on the supposition that they arose in that range, and sub- 

 sequently migrated to the western range. The distribution 

 of the two species turritella and nigrolabris and their rela- 

 tions, in converging lines of affinity and distribution, point 

 to turritella of the southernmost valleys as the probable an- 

 cestor of the entire group. There is one doubt in my mind, 

 that is whether A. variegata and turritella are so closely con- 

 nected as is here represented. I have thought that more ma- 

 terials might transfer this species and its affines to the same 

 series with rubens. This removal, however, would resolve the 

 group into one series and still leave the argument intact for 

 this series, which would then be a single line of species from 

 turritella, nigrolabris, rudis, spirizona. 



III. Relationships and migrations of Laminella?, according to 



Hyatt. 



The species of this genus found on Oahu are much larger 

 and stouter shells than those of Molokai (which are decid- 

 edly dwarfish), and somewhat larger also than those of Maui 



