PARTULINA, MOLOKAI. 77 



Series of P. mighelsiana. MOLOKAI. 



Rather small shells with a high polish, weak or almost 

 wanting spiral stria tion, and bright coloring yellow often 

 with white or chestnut bands, or white or chestnut through- 

 out; never striped longitudinally; lip unexpanded. Embryo 

 spirally banded or plain. 



These shells are related to the variabilis group of Lanai 

 and the porcellana group of Maui. Whether they belong to 

 the Oahuan group Achatinellastrum, or represent a branch of 

 Partulina convergent towards that Oahuan group, remains 

 uncertain. In Hyatt's earlier writings he placed part of these 

 species in Achatinellastrum, but later he doubted this group- 

 ing, and was disposed to view them as modified Partulinee. 

 As there are Maui-Molokai types in Oahu, such as Laminella 

 and Partulina dubia, there seems no good reason why some 

 Achatinellas of Oahuan type should not occur in the more 

 eastern islands. 



For the present I leave the mighelsiana group in Partulina 

 for the reason that among the related Mauian species it would 

 be very difficult to draw the line between Partulina and Acha- 

 tinellastrum. The coloration of the embryonic shell is more 

 like that of P. virgulata than like the ordinary Partulinas. 

 Dr. Oooke suggested that in view of the numerous forms of 

 intermediate character between the three conventional species 

 of the mighelsiana group, it would be more logical to rank 

 bella and polita as subspecies of mighelsiana. 



43. P. MIGHELSIANA (Pfeiffer) . PI. 18, figs. 10 to 17. 



" Shell ovate-coniform, smooth, opaque, glossy; snow-white 

 variegated with ashy streaks. Spire conic, the apex rather 

 acute, suture somewhat margined. Whorls 5^, convex, the 

 last encircled with a blackish line (sometimes doubled) below 

 the middle. Columellar fold strong, tooth-like, chestnut col- 

 ored at the base. Aperture semi-oval, brown-margined ; peris- 

 tome simple, acute. Length 17, diam. 8 mm., aperture 8 T /2 

 mm. long, 4 wide (Pfr.). 



Molokai (Cuming coll.) : Kalae (Baldwin, Thaanum) ; Kilo- 



