OPEAS, POLYNESIA. 185 



cidedly shorter, and the whole shell usually more lengthened. 

 The names B. oparanus and B. pyrgiscus Pfr., 8. upolensis 

 and 8. novemgyratus Mousson seem to 'be based upon vary- 

 ing forms of species (2). It is likely that further study with 

 large series, would result in the recognition of a number of 

 local subspecies; but this must be left to some one who can 

 give some weeks to the question. 



Pfefffer did not illustrate his type of oparanum. Reeve's 

 figure of a supposed topotype, copied in my pi. 22, fig. 12, 

 may not be the same species. I have seen numerous speci- 

 mens from the following groups: Hawaii, Marquesas, Pau- 

 motu, Society. 



In the Hawaiian Is. the form has been called 0. pyrgiscus 

 Pfr. The original description and figure follow. B. pyrgis- 

 cus, pi. 22, fig. 5. Shell subperforate, turrite, rather solid, 

 very lightly striate, whitish; spire elongate, the apex rather 

 acute, suture deep. Whorls 9, a little convex, the last two- 

 ninths the total length, not tapering at base ; columella very 

 slightly arcuate. Aperture slightly oblique, angular-oval ; 

 peristorne simple, unexpanded, the columellar margin nar- 

 rowly reflexed, subadnate. Length 13, diam. 3, aperture 2.75 

 x 1.5 mm. Sandwich Is. (Pfr.}. 



A large specimen from Maui is figured, pi. 22, fig. 1. It 

 measures, length 11.3, diam. 3, aperture 3 mm., with 8!/2 

 whorls. One from Oahu, pi. 22, fig. 2, is 9.3 mm. long, diam. 



2.4, aperture 2.4 mm., whorls 8y 2 . The suture is distinctly 

 crenulate. Others are before me from Hilo, Hawaii and 

 Kaunakakai, Molokai (R. C. McGregor, 1900), and from 

 Manoa valley and Round Top, Oahu, and Kona crater, Kona, 

 Hawaii (Bernice Pauahi Bishop Museum). Young shells, 

 one-third to a half grown, have much the appearance of 

 0. gracile. The smallest one I have seen containing an egg 

 is 7 mm. long. 



Marquesas Is. A large series consists wholly of rather 

 small and short though mature examples, pi. 22, fig. 3, length 



9.5, diam. 2.8, aperture 2.8 mm., with 8 whorls.' The suture 

 is not crenulate, but the whorl bulges abruptly below it. The 

 columella is concave and thin below. 



