MANUAL OF CONCHOLOGY 



Family PUPILLID^E Turton. 

 Subfamily VERTIGININ.E, continued. 



Genus PRONESOPUPA Iredale. 



Pronesopupa IREDALE, Proc. Malac. Soc. London, x, 1913, 

 p. 384, for P. sen-ex. 



The shell is similar to Nesopupa except that the aperture 

 is toothless; outer lip reflected, the lip insertions remote. 

 Living on trees or plants. 



The species are illustrated on plate 1. 



The arboreal P. sen ex, of Kermadec, type of this genus, is 

 not known to us by specimens, and we have not seen P. sim- 

 plaria Pease, of the Marquesas, which appears to belong here. 

 The Hawaiian species which we now place in Pronesopupa by 

 having cuticular laminae on the ribs, or "membranous ribs", 

 agree with numerous toothed Hawaiian forms of Nesopupa. 

 It appears likely that they were derived from the Limbati 

 pupa group of Nesopupa by loss of teeth. It is quite possible 

 that Pronesopupa senex is a similar derivative from some 

 other dentate stock of southern Nesopupce. 



The negative character of being toothless has little weight 

 in phylogeny, but we have nothing better at present; when 

 the radulae of P. senex and the Hawaiian species can be com- 

 pared a further step may be taken. 



1. PRONESOPUPA SENEX Iredale. PL 1, figs. 8, 9. 



"Shell minute, pupoid, dextral, few whorls. Color brown. 

 Whorls 4 ; the first whorl and a half smooth ; the succeeding 

 whorls have a sculpture of distant sharp lamellae, the inter- 

 vening spaces threaded with stria? ; in some shells the lamellae 



