04 THE NAUTILUS. 



lations of these snails are still uncertain. No member of the series 

 has been dissected. 



One of the first forms described was Steyodera angusticollis Mar- 

 tens (pi. 2, fig. 1, 2, 3), a sinistral snail from the Yangtse valley, 

 with the last whorl distorted, making the throat very narrow. It 

 has not before been noticed that there is a weak and shallow groove 

 on the upper part of the last whorl (indicated in fig. 1), and another 

 one, very weak and shallow, on the base. These vestigeal furrows, 

 which would scarcely be noticed, evidently represent structures far 

 better developed in the following species. 



Helix triscalpta Martens, type of Ancey's group Traumatophora, 

 is shaped like Stegodera, but has a regular coil, and is dextral. 

 There are three furrows in the latter part of the last whorl, marked 

 inside by irregular lamellae. The texture and granose sculpture are 

 like Stegodera. 



Helix horrida Pfr. and its allies are quite different. The spire is 

 sunken, as in Chloritis, the peristome continued in a cord across the 

 parietal wall, and the last whorl has two deep furrows, one basal, 

 the other above the periphery. This and all the preceding have the 

 apical whorl smooth and glossy. (See pi. 2, figs. 4-6.) 



Another series has the apical whorl granulated. There are two 

 or three furrows outside, with corresponding prominences within. 

 Helix trisinuata type of Moellendorffia Ancey, is typical of this group 

 (pi. 2, figs. 7, 8). 



The absence of any internal lamellae or barriers on the parietal 

 wall differentiate all of the above from Plectopylis and Gorilla, while 

 the granose surface, external furrows, etc., indicate that the various 

 members are related to one another. The tendency to have two ex- 

 ternal pits or furrows in definite positions shows a great likeness to 

 certain forms of Chloritis, and the very closely related group Plan- 

 ispira, such as C. bifoveata Bs., P. endoptycha Mts., porcellana Grat., 

 infracta Marts., etc. 1 The correspondence is so close that I have 

 now little doubt that this Chinese series of Helices is closely related 

 to the genus Chloritis, though the full demonstration awaits an ex- 

 amination of the soft anatomy. Pending this, I would suggest the 

 following classification of the species : 



1 Mr. Sykes has proposed a section Vulnus for these pitted Planispiras. J. oi 

 Malak., 1904, p. 88. 



