LYROPUPA. 267 



L. micro, and especially L. ovatula. It is larger than the 

 former, with far stronger sculpture. L. ovatula of Oahu is 

 very closely related, but the prominent basal crest and hump 

 distinguish it. The lower palatal and basal folds are stronger 

 in L. o. kona. 



The chief variations noticed among the numerous specimens 

 are in shape (see measurements) and strength of the ribs, as 

 shown in the figures. 



A single specimen (pi. 26, fig. 5) was among Lyropupae 

 taken by the authors on Molokai at Moomomi on the north 

 coast, at the end of the escarpment running north from Mauna 

 Loa. It measures, length 2.25, diam. 1.4 mm., and appears 

 to differ in no respect from those of the Kona slope of Hawaii. 



Probably the species will be found in Maui when fossil 

 material from that island comes to hand. 



19. LYROPUPA PLAGIOPTYX P. & C., n. sp. PL 24, figs. 8, 11, 12. 



The shell is ovate, rather solid, the whorls strongly convex, 

 the greatest convexity below the suture, with sculpture of 

 regular, strong, arcuate ribs, about 15 on the last whorl. The 

 last whorl tapers downwards. Its last half is swollen and 

 strongly ribbed below the suture, encircled in the middle with 

 a rather deep sulcus, crossed by the ribs. Below this is a 

 short, sharp lateral sulcus (over the lower palatal fold), and 

 on the basal convexity are two very short impressions. The 

 ribs diminish in size and are increased in number on ,the basal 

 half of the last half whorl. Aperture as usual in the group 

 externally. The columellar lamella is strongly crescentic, as 

 in L. ovatula. The crest of the upper palatal fold is uneven. 

 Below its inner end there is a small but high and short vertical 

 tubercle. The lower palatal fold is immersed but visible in a 

 front view, short, high and oblique, its outer end sloping 

 steeply downward. 



Length 2.15, diam. 1.3 mm. 



Oahu : Kawaihapai, on a steep, wooded hillside about 500 

 ft. above the plain and perhaps % mile from the sea (Cooke 

 & Pilsbry, 1913). 



This species, found only dead in the surface debris, is re- 



