12 PRONESOPUPA. 



vex outlines, the whorls very convex and separated by a deep 

 suture. Whorls 4, the embryonic (under the microscope) 

 not smooth, irregularly punctate, gradually becoming costu- 

 late, the two last whorls costulate. The last whorl ascends 

 slightly near the aperture, is almost evenly ribbed with 35-40 

 costulse ; these are oblique, rather low, with slightly ragged, 

 thin, membranous outer margins, and of an almost uniform 

 height. The aperture is subcircular, toothless; outer margin 

 expanded, thin, the columella slightly swollen near the middle, 

 but not furnished with a lamella ; columellar margin broadly 

 dilated. 



Length 1.45, diarn. 1, aperture, greatest length 0.67 mm. 



The specimens selected for the above description are 

 slightly larger than indicated by Mighels, and also slightly 

 broader in proportion to their length, with a half whorl more. 

 I do not know of any form as small or narrow as Mighels' 

 specimens and he may have made a slight error in his meas- 

 urements. 



Specimens from Tantalus agree essentially with those from 

 Nuuanu, except that the color is a clear light brown, without 

 a greenish tinge, and the aperture is slightly larger without 

 the slight swelling on the inner margin of the columella. One 

 of the specimens measures: length 1.53, diam. 1.04, aperture 

 0.79 mm. 



In embryonic specimens of nearly two whorls the umbilicus 

 is represented by a minute cleft. The first whorl is furnished 

 with a few raised, thin spiral lines, the transverse riblets set 

 in abruptly at the beginning of the second whorl. The raised 

 spiral lines are also found on immature specimens with 3% 

 whorls. 



Specimens from Palehua and Kaala, Waianae Mts., are 

 almost duplicates of those from Tantalus, except that the 

 apertures of the Kaala specimens are truncate-ovate rather 

 than subcircular. 



A single specimen from Koholuamanu, Kauai, agrees very 

 closely with the specimens from Luakaha in size, color, form 

 and character of costulations. The columella is not, however, 

 slightly swollen near its middle, but uniformly slightly 

 concave. 



