122 THE NAUTILUS. 



I agree completely with ^Ir. Pilsbry in regarding the numerous 

 "genera" of the Charopidce instituted by our Australasian confreres 

 as subgenera of Paiula. Thus Patula is a completely cosmopolitan 

 genus. The true HeUcidce do not exist in New Zealand. In 

 my paper already cited, I have restricted the family HeUcidce (p. 

 426) to the genera having a dart sack or sacks (belogonous). These 

 are the following : 



1. Xerophila (Held.) v. Ih. 



2. Fridicicola (Held.) v. Ih. 



3. Helix (L.) V. Ih. 



4. Carnpykea (Beck) v. Ih. 



5. Gonostoma Held. 



6. Dorcasia (Gray) v. Ih. 



7. Cochlodyla Fer. 



The genus Helix comprises Tachea, Pomatia, Iberus, Macularia. 

 The Helices of U. S. are not belogonous and form my genus Neo- 

 helix (p. 482), corresponding in general to what Mr. Pilsbry called 

 Polygyra. But as Mr. Pilsbry's genus also included Gonostoma 

 and Vallonia, these genera are not synonymous. It is not at all 

 convenient to give the name Polygyra to the section Polygyra and 

 also to a greater group which each zoologist defines in a different 

 manner. The genus Neohellx is a very natural one, but its system- 

 atic position Avill not be evident until the origin and affinities of the 

 genus are demonstrated, and this, I believe, will be made out by 

 farther anatomical and embryological studies. 



I provisionally give the name Parahelix (p. 492) to all Helices 

 which are not HeUcidce or Neohellx. The anatomy of the Parahelix 

 group is almost unknown. 



The family of HeUcidce is not represented (excepting the imported 

 genera) in the U. S. east of the Rocky Mountains ; and there seems 

 no paleontological evidence that they formerly existed there. The 

 genus Carnpykea extends from Europe and Asia to California, 

 Central America and eastern South America. These South Amer- 

 ican Helices without doubt are pliocene immigrants. No HeUcidce 

 are found in Australia, New Zealand or Polynesia. Nor in Chile 

 and La Plata tertiary beds no true HeUcidce occur. There can be 

 no doubt that the family HeUcidce is a palsearctic one, which in 

 tertiary time extended to America. 



I agree in general with the observations made by Mr. Pilsbry on 

 the relations of the New Zealand fauna ; but I believe that Mr. 



