Descriptions of New Species of Achatinella. 243 



shading of the varieties of different species into one another, 

 has in many instances been noted ; but the affinities are more 

 complicated than would appear from the descriptions. From 

 this cause, together with the perplexity arising from dextral 

 and sinistral varieties, from lack of specimens representing 

 many of the forms of the genus, and from inability to ascertain 

 the geographical relations of the species, unavoidable errors 

 found their way into Reeve's Monograph of the genus, from 

 which confusion has arisen in the nomenclature of the species 

 of this group especially. Additional error has since been 

 introduced, by the description, under new names, of certain 

 specimens of well known shells, which the demand for new and 

 beautiful species had subjected to artificial treatment. So suc- 

 cessful was the deception that some are still received as 

 genuine, which I am persuaded belong to this class. 



A. vulpina Fer. was described as a sinistral species, and ac- 

 cordingly the name was applied only to sinistral specimens. 

 The dextral varieties of this species were described by Reeve 

 under the names of A. producta and A. bilineata, while the 

 name vulpina was transferred by him to another species, which 

 we have now described as A. varia, to which was added, as a 

 variety, the distinct species A. livida Swains., and also by 

 Pfeiffer, A. Stewarti Green. Other dextral specimens, which 

 have been described by Dr. Newcomb under the names A. 

 venulata and A. hybrida, differ from the dextral type chiefly 

 in the arrangements of the color, which I think are not specific 

 characters, if indeed they are natural. A. venulata, var. a, I 

 take to be the green variety of A. Stewarti. 



A. Johnsonii and A. aplustre Newc. are fine specimens of 

 A. Byronii, the one entirely, and the other partially deprived 

 of its epidermis. 



The name A. Byronii has given place to A. pulcherrima, 

 which belongs to a species similar in outline, but of very dis- 

 tinct affinities. 



A. livida Swains, is much smaller than A. vidpina Fer. and 



