20 PUPISOMA. 



varied. Stoliczka and Blanford thought it a subdivision of 

 Pupa, having in mind the larger species, lignicola and eve- 

 zardi. Von Moellendorff, who knew only orcula-like species, 

 referred it to what he considered the Fmticicolid group, in 

 the neighborhood of Acanthinula and Zoogenites. Later esti- 

 mates were less sagacious. The present writer placed it in 

 the Endodontidcc, but expressed a suspicion that it might 

 belong to Pupidcc. Finally Godwin-Austen placed it in the 

 subfamily Thysanotincc of the Endodontidcc. 



In restoring the genus to the Pupillidce, and placing it in 

 the subfamily Vertiginincc, the writer has been influenced 

 chiefly by the identical type of teeth and the absence of in- 

 ferior tentacles. Moreover, the shell, in the type species, P. 

 lignicola, approximates closely to such Nesopupae as N. ba/r- 

 rackporensis in sculpture, and is utterly unlike any Endo- 

 dontid snail. The teeth of the shell of P. lignicola, such as 

 they are, are normal for a Pupillid snail, but not like any 

 Endodontid. The genus may be regarded as an arboreal 

 derivative of Nesopupa, which has been modified like the 

 HaAvaiiaii Pronesopupse (likewise arboreal or folicolous) by 

 decadence or loss of teeth in the aperture, simplification of 

 the peristome and increasing tenuity of the shell. 



P. dioscoricola in America and P. orciila of the Oriental 

 fauna are so similar that transportation by commerce seems 

 possible or even likely ; yet other and strongly differentiated 

 forms show that various species are certainly indigenous in 

 both hemispheres. Former communication of the herds may 

 have been around the north Pacific. 



Pnpisoma comprises about a dozen well-established species, 

 divided between America and the Old World. As many 

 more doubtful or nominal species have been described by 

 authors who knew little or nothing of previous work, or who 

 did not compare their supposed novelties with the widespread 

 P. dioscoricola and P. orcula. There has been no general re- 

 vision of the genus hitherto, and its species have been scat- 

 tered through several genera. 



Minute snails such as Pup-illidic and Vdllotiiidcc frequently 

 occupy far greater areas than the associated larger land mol- 



