THE NAUTILUS. 65 



NOTES ON THE MOLLUSCA OF FORRESTER ISLAND, ALASKA. 



BY GEORGE WILLETT. 



During the past four months (1914 to 1917 inclusive), which 

 were spent by the writer on Forrester Island, Alaska, some at- 

 tention was given to the study of the mollusca of the locality. 

 The shore line was rather thoroughly traversed and some dredg- 

 ing was done in various depths down to seventy-five fathoms. 



Forrester Island lies well out to sea, a few miles north of the 

 Canadian boundary line. It is about fifteen miles west of Dall 

 Island, and seventy-five miles out from the mainland shore. 

 The island is small, being approximately five miles in length 

 and from a half mile to a mile and a half in width. It is very 

 rocky along shore but is well timbered from the high-water line 

 to the summits of the hills. There are a number of small islets 

 and groups of rocks lying off the main island and practically all 

 of these were visited one or more times. 



As Forrester Island is well within the sweep of the Japan 

 current, the water is much warmer than in the inside channels 

 around Dall and Prince of Wales islands. The effect of this 

 difference in temperature is shown in the fact that several species 

 of shells that occur in 10-15 fathoms in inside waters were not 

 found in less than 40-50 fathoms at Forrester Island. Also a 

 number of species that were rather common on Dall and Prince 

 of Wales islands were not noted on Forrester Island at all. As 

 there are neither sand beaches nor mud flats on the island, 

 many forms requiring such situations were conspicuously ab- 

 sent. The tidal currents in the vicinity are very strong at 

 times, and it is quite possible that some species of which frag- 

 ments or dead shells were found do not properly belong to the 

 island fauna but were carried to the locality by the strong cur- 

 rents. One of the most interesting features of this region from 

 a conchological standpoint is the fact that in many instances it 

 seems to be a meeting point between boreal species and those 

 from the southern fauna. 



A number of species taken have since been described as new. 

 In such cases I have mentioned the paper in which the descrip- 



