PREFACE. 



The present volume is devoted to the oriental Helices, including 

 the large species of Japan, China, the East Indies, Australia, 

 Madagascar and Ceylon. First place has been given to Stegodera, a 

 Chinese group of uncertain affinities, containing forms with curiously 

 toothed and contorted apertures. Pedinogyra and Ampelita follow, 

 each of these being apparently an isolated group, not united by 

 known characters to other subgenera. A number of groups are 

 then discussed which the writer has brought together on account of 

 the novel character of their ova, which are relatively enormous, the 

 embryonic shell often exceeding one-third the diameter of the adult. 

 To this macr embryonic group, as it may be termed, belong Helico- 

 phanta, Stylodonta, Acavus and Panda the largest of Helices. The 

 great series of which Hadra, Xanthomelon and Sphcerospira are lead- 

 ing forms is then considered ; and finally are monographed Plani- 

 spira, Obba, Chloritis, and the forms grouping around them. 



Philadelphia, April, 1890. H. A. P. 



