PTYCHAL^A. 273 



peristome is continuous, the dorsal impressions are not deep, 

 and it could hardly have been described as flexuose forte 

 costata. 



It was these specimens from Pease which the senior author 

 referred to as Nesopupa (Lyropupa] costata, in Proc. A. N. S. 

 Phila., 1900, p. 432. Other authors who have mentioned the 

 species knew it only by Pease's description. 



At present therefore V. costata appears to be a lost species 

 of uncertain genus ; unless the type comes to light it must be 

 dropped as unrecognizable. 



Genus PTYCHAL^A Boettger. 



This volume, pp. 157, 220. 



This group was proposed for a Lower Miocene species of 

 Europe ; a recent species of the Benin Islands appears to agree, 

 but the writer has not seen the fossil genotype. 



They differ from Nesopupa chiefly by having a strong crest 

 behind the lip, as in many Vertigos. This is not usually a 

 character of much importance, but it is absent in the long 

 series of species referred to Nesopupa. Boettger himself made 

 a distinction between Ptychalosa and Ptychochilns (= Neso- 

 pupa), both of which he recognized in the European Tertiary. 



We now consider Ptychalaea incorrectly placed in Vertigo. 

 We are strongly disposed to subordinate Nesopupa, Costigo 

 and Protiesopupa to Ptychalaea as subgenera ; yet specimens of 

 the fossil type of the latter are not at hand, and species inter- 

 mediate between Ptychalaea, and Nesopupa have not been 

 found. At present we admit several genera, Nesopupa, 

 Pronesopupa and Costigo, among the Polynesian and Oriental 

 Vertigininae as a temporary expedient rather than as an ex- 

 pression of definite conviction. It is quite probable that a 

 study of the dentition would yield characters of value in 

 this inquiry. 



1. PTYCHALAEA DEDECORA (Pils.). P. 158. 



The fossil species P. flexidms Reuss, and possibly ca-pellinn 

 Sacco belong here. The other species enumerated under 

 Ptychal&a on p. 220 belong to Nesopupa. 



