262 LYROPUPA. 



towards the aperture. The internal palatal tubercles are 

 strongly developed, the lower palatal fold otherwise very low, 

 in form of a rounded callus pad (fig. 2). 



Length 2.25, diam. 1.1 mm. ; 5% whorls ; type. 



Length 2, diam. 1.2 mm. ; 5 whorls. 



Length 1.8, diam. 1.1 mm. ; 4% whorls. 



Oahu: abundant in debris of the "coral bluff" 1% miles 

 west of Kahuku (Cooke & Pilsbry) ; Maleakahana (Cooke). 



It is readily distinguishable by the irregular sculpture. The 

 internal structure is much as in ovatula, but it has not the 

 strongly differentiated basal crest of that. The parietal 

 lamella penetrates much further than in Diamond Head 

 perlonga, and the columellar plate is larger and more curved. 



Occasional individuals are very short but of about the dia- 

 meter of the longer ones, as in the third measurement given 

 above. Sometimes there is an indistinct dorsal hump near the 

 base of the last whorl. 



A small form, resembling the smallest found at Kahuku, has 

 been taken at Maleakahana (pi. 25, fig. 10) ; dune deposit west 

 of the Laie stream, between the highway and the sea (Cooke 

 & Pilsbry), on the north shore, near the northwestern point 

 of Oahu. 



There is an inconspicuous, rounded basi-dorsal prominence ; 

 the lower palatal is rather strongly developed. It is wider 

 than L. micra of the same length, but approaches it somewhat 

 by the incipient hump. Length 2, diam. 1.1 mm. 



16&. L. perlonga filocostata C. & P., n. subsp. PL 23, fig. 12, 

 Specimens from Kauai and Niihau differ from those from 

 the other islands in that the surface is crowded with slender, 

 oblique, flexuous costee (sometimes quite irregular), about 28 

 to 30 on the last whorl. All the specimens examined are fossil. 

 In some of these the delicate spiral striae are still present. 

 The lower palatal fold is low but comparatively strongly 

 developed, and appears to be weakly united with the strong, 

 oblique tubercle further in. There is a weak basal fold, fol- 

 lowed within by another callus tubercle. 



Length 2.15, diam. 1.15, apert. 0.8 mm.; 5^ whorls; Kauai: 

 Limahuli, type (Cooke). 



