288 ACHATINELLA CESTUS. 



typical color-form of cestus. Whether the Gulick lot of this 

 mutation was also in a mixed or hybrid colony is not known. 

 Although this form is not known to occur as a pure race, it 

 may be convenient for reference to designate it as color-form 

 or mutation simulator. It is interesting as showing the evolu- 

 tion of a banded form derived from a streaked pattern. 

 Further instances of such transformation will be found under 

 various western species. Form simulator has been found only 

 in Palolo, and must now be very rare. 



In another form from Palolo, taken by Gulick, the streaks 

 are light brownish olive, and an indistinct, sutural band is 

 somewhat rusty. There are one or two light lines at the 

 periphery, and some dark bands around the columella. 

 These occurred with other specimens of more normal pattern. 



Waialae. Gulick found typical cestus. Also a form which 

 he identified as A. forbesiana Pfr., I think correctly. The 

 streaks vary from russet to dusky drab, cut by white bands 

 and lines which may be few or very numerous (pi. 52, figs. 

 11, lla, 11&). Lip brownish. The original description of A. 

 forbesiana will be found below. 



In Waialae iki Mr. Spalding found somewhat similar shells, 

 dark cestus with a white belt, 3 sinistral specimens. On top 

 of the Waialae iki and Wailupe ridge Mr. Wilder obtained 

 specimens with two white basal bands. 



Wailupe. Gulick obtained typical cestus, some with the 

 markings very weak, and also a multilineate form resembling 

 the forbesiana of Waialae (pi. 52, figs. 13, 13&). A fine series 

 from Mr. Thaanum, pi. 52, figs. 9, 9a, represents a pure colony 

 of forbesiana. The streaks are sepia, dusky drab or dark 

 plumbeous ; white spiral lines few or many ; interior light blue. 

 A series from the Wailupe-Niu ridge taken by Mr. Spalding 

 are probably from the same place. A few have a narrow 

 white band at the periphery. It varies to quite pale color 

 (pi. 52, fig. 10). 



Niu. In a series in coll. C. M. Cooke the shells are similar 

 to the preceding, some browner, approaching the Waialae 

 color. 



A. forbesiana is a limital southeastern race of cestus, and 



