LYBOPUPA. 261 



smaller than the typical perl&nga, with closer costee, and have 

 distinct though minute close spiral striae in the intercostal 

 spaces. There are about 20 riblets on the last whorl. 



The lower palatal fold is comma-shaped (pi. 26, fig. 4) in 

 some examples, but in others there is a very low anterior 

 callous pad, connected with the higher posterior portion (pi. 

 26, fig. 7). This may be a more mature phase. Length 2.15, 

 diam. 1.2 mm. The shell of nearly 3 whorls is drawn in pi. 23, 

 figs. 13, 14; diam. 1 mm. 



At Kaelepulu, Kailua, on a low lime-rock bluff about a quar- 

 ter mile from the shore, this species is abundant and variable, 

 extreme specimens measuring : 



Length 2.4, diam. 0.96 mm. ; 6 whorls (pi. 24, fig. 10). 



Length 1.9, diam. 1 mm. ; nearly 5 whorls (pi. 24, fig. 9). 



It occurs with L. ovatula, L. micra and L. m. percostata, 

 also with other land shells, all now extinct in that place. The 

 lower palatal fold is reduced to a very low, small rounded 

 callus, difficult to see. The same form is found on the neck 

 of Mokapu peninsula, likewise extinct. 



Form cyUndrata, pi. 23, fig. 8. Specimens from a few locali- 

 ties differ somewhat from the typical form. The shells are 

 longer, more cylindrical in outline and the third whorl is 

 usually slightly more swollen and wider than the lower whorls. 

 The lower palatal fold is shorter than in the forms described 

 above. 



Length 2.6, diam. 1.05, apert. 0.73 mm. ; 5% whorls. Oahu : 

 Makua ; type loc. 



Length 2.7, diam. 1.1, apert. 0.8 mm.; 6*4 whorls. Oahu: 

 Diamond Head, sea-cliffs. 



16a. Lyropiipa perlonga ititerrupta P. & C., n. subsp. PL 22, 

 figs. 5 ; pi. 25, figs. 1 to 4, 10. 



The shell is cylindric, cinnamon or somewhat darker, the 

 whorls flattened, swollen along the suture, with sculpture of 

 irregular ribs, on the last whorl or two interrupted in the 

 middle. Impressions on the last half whorl are strongly de- 

 veloped. The parietal lamella is very long, curving at its 

 inner end . Columellar lamella is crescentic, both ends curving 



