PREFACE. 



As the title-page indicates, this monograph contains the re- 

 sults of work by two authors. The Achatinellida? had been 

 studied by Professor Alpheus Hyatt for many years prior to his 

 death in 1902. "It is unfortunate that he never fully wrote 

 out the results of his studies upon these shells, the manuscript 

 which was found after his death being very incomplete, espe- 

 cially upon specific points; and although many of his descrip- 

 tions of the species themselves were completed, yet his con- 

 clusions respecting their relationships and migrations are only 

 vaguely referred to." 



Professor Hyatt's notes, relating to about 130 of the 280 species 

 treated in this volume, were submitted to the junior author in 

 the spring of 1906, with the condition that they be incorporated 

 in the present monograph so far as practicable. The manu- 

 script received contains all of his notes descriptive of genera 

 and species, their localities, classification and relationships, also 

 sketches of his views upon the migrations of the Amastrse of 

 Oahu and of the LaminellaB, which are printed in full in Ap- 

 pendix B (p. 358). Aside from this, the manuscripts include 

 none of Hyatt's deductions and theoretic conclusions bearing on 

 the origin, evolution or zoogeography of Achatinellidse; this 

 material having been reserved for separate publication. The 

 junior author is therefore alone responsible for zoogeographic 

 views expressed herein, except in so far as these views coincide 

 with those of Hyatt's essay forming Appendix R.^ It should 

 be said that Hyatt's theoretic views on the migrations of Acha- 

 tinellidce, as expressed in Appendix B (pp. 358 to 368) are 

 directly opposed to those of the junior author. Those inter- 



1 Alfred Goldsborough Mayer in Popular Science Monthly, February, 1911. 



(vii) 



