104 OXYSTYLA- 



Most authors, however, including Slmttlewortli, in his valuable mon- 

 ograph, have treated them as distinct, and I adopt this plan ; hut I 

 confess that in some cases it is very difficult to decide to which species 

 a single specimen may helong." The material I have studied fully 

 supports Dr. von Martens' remarks just ({noted. It should he added 

 that there are several species of the undafa-princeps group, such as 

 obdiictct and longa, which are readily distinguishable and undoubtedly 

 "good" species, and in fact forms occur of every grade between species 

 and mere local races. There is no particular advantage in lumping 

 them under one name, as the forms are definitely limited geographi- 

 cally, and the knowledge already gained of their variation and dis- 

 tribution would be largely lost by lumping all of them under one or 

 two of the old names. 



The species are herein grouped geographically under (1) Mexican 

 and Central American, (2) species of the Antilles and Florida, and 

 (3) South American. This arrangement separates some closely- 

 allied forms, such as 0. imd<ifn, maracaibensis and femssaci, but is 

 probably more convenient than a strictly natural sequence. 



The oldest description of a species of this genus, Buccinnnt zebra 

 Miiller, Vermium Terrestrium et Fluviatilium, ii, p. 1.>S (1774), 

 would apply to various species, but is so vague that it cannot be fixed 

 upon any one of them. As illustrations of his specie^. Miiller cites 

 numerous figures: Lister, pi. 11, f. 6 = -Pent/eras ; !>, 4 and 10, 5 

 = Limtcolarfaf \ ;")S(), 34= Orllialiriis /n-inceps? or mtdafiis ? young; 

 />"*, 33 = Achatina ftiUca ; Petiver. (la/ophvl. 44, 7 = a uniform 

 while <h-i/sti//a, possibly O. maracaiberuts f. imitator; Selia, The- 

 saurus, pi. .')'.(, f. f4, ;">."> = (). feriissaci f and f. o(), ">1 = 0. nn-lnna- 

 i'ln ilns, trii-l art us or imitator. 



The terms of the specific description exclude Arlmtina. The name 

 practically covers the entire ueniis Oxystyld) with similai-Iv marked 

 specie*; of Li m icula r ia ; Imt ill my opinion neither the mrlannrln>i!us- 

 like form selected by Shuttlewortb, nor the O. inidat/ts of llrnguiere 

 can fairly be called zrlra ; the first because Miiller's name and de- 

 scription point rather to a zebra-striped and not a three-banded shell, 

 the second hecaii-e iiinliitiis was the first s|n-cie> to lie -r.jiTHated from 

 Miiller's composite group, and hence has a valid claim to retention. 



There is a specimen in Miiller's collection which Mi'irch took tor 

 the type, apparently either melanockeilui, tri<-iin-tnx or imitator; but 

 Miiller states thai the type is in Spenglcr's collection. 



