NOTES ON ZOOGEOGRAPHY. xli 



yet very imperfectly known. The spectacular gorges of the 

 Kohala mountains appeal to me as a promising fielcl. More- 

 over, it is an important point from the zoogeographic stand- 

 point. On all the islands, the fossil beds promise good enter- 

 tainment. 



The snail fauna, outside of Achatinelloid forms, has been 

 only imperfectly worked up, and many undescribed species 

 are now known. We cannot doubt that a large number re- 

 mains to be discovered. On the whole, it appears that the 

 work to be done in faunistics alone is much more than one 

 generation can accomplish. 



Much in the preceding pages may seem trite to Hawaiian 

 naturalists, accustomed from boyhood to scale the rugged, 

 jungle-clad mountains of their exquisite islands in the quest 

 of shells, or wild goats. I wxmld not presume to write for 

 them upon many topics which have been touched on here, in 

 order that conchologists elsewhere may better understand the 

 Hawaiian faunas. 



NOTES ON THE ZOOGEOGRAPHY OF ACHATINELLOID SNAILS. 



(Supplemental to Vol. XXI, pp. xi-xix.) 



Arguing from the distribution of the living snail fauna, 

 the theory was advocated in Vol. XXI that the islands were 

 formerly united, allowing land and fresh-water snails and 

 other land animals and plants to pass from one to another. 

 The exploitation of the deposits of fossil land shells lends ef- 

 fective support to this theory. 



In the recent fauna, the species of Achatinellidge and 

 Amastridae are special to each island, though in a few cases 

 the difference between some species of two islands is small. 

 In the Pleistocene fauna the relationship was closer. Oahu 

 had a Partulina of Molokaian type (A. montagui). The 

 Amastra umbilicata group is found to be common to every- 

 one of the islands. A. umbilicata of Oahu and Molokai is 

 barely distinguishable from A. morticina of Maui and 

 Kahoolawe, and A. ultima of Hawaii is very closely related. 



In Leptachatina, the group of forms having a posterior 

 tubercle and groove in the aperture, formerly known only by 



