312 AMASTRA, HAWAII. 



" Length 23, diam. 18 mm.; 7 whorls " (Baldwin). 



Hawaii: Palihoukapapa, on the Hamakua slope of Mauna 

 Kea, at an elevation of 4000 ft., fossil in a deposit about a foot 

 below the surface (Eugene Homer). 



Amastra senilis BALDWIN, Nautilus, xvii, July, 1903, p. 35. 

 HENSHAW, Journ. of Malacology, xi, p. 63. 



The largest Hawaiian Amastra, recalling A. kauaiensis in 

 general contour, but with the thin texture and striate embryo 

 of A. melanosis and its allies. Baldwin states that there is 

 ' ' a thick parietal callosity, ' ' but this is evidently only in old 

 shells, as the parietal callus is quite thin in the cotypes which 

 he sent for figuring. The species is most nearly related to 

 A. melanosis, and is remarkable for its open umbilicus, as in 

 Cyclamastra. 



106. A. MELANOSIS (Newcomb). PI. 47, figs. 1, 2, 6, 7, 9. 



Shell dextral, thin, conically depressed ; apex acute ; whorls 

 5, rounded, the last inflated ; suture well-impressed, aperture 

 subrotund; lip simple, thin; columella straight, white, and 

 terminating in a very oblique plait; color black. Length 8, 

 diam. five- twentieths of an inch (Newc.). 



Hawaii (Newcomb) ; Hamakua (Baldwin) ; Kukaiau 

 (Thaanum). 



Achatinella melanosis NEWC., P. Z. S., 1853, p. 144, pi. 23, 

 fig. 41. 



The typical form of melanosis as figured by Newcomb 

 pi. 47, fig. 6) is more widely conic than any specimens we 

 have seen. Probably the type colony has not been rediscov- 

 ered. The locality is unknown, but probably the type came 

 from somewhere in Hamakua district, north from Mauna 

 Kea. 



Specimens from Hamakua, received from Mr. Baldwin 

 are figured, pi. 47, figs. 1, 2, 9. The embryonic whorls have 

 a very fine sculpture of sharp, close, curved striae. Later 

 whorls have more oblique, irregular growth-lines, and are 

 quite convex. Sometimes by the slow descent of the last 

 whorl, a peripheral angle is disclosed on the penultimate, 

 while in other shells it is covered. The last whorl is more 



