66 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lOO 



in which there are duplicate depths. In the table on dredging stations 

 the reader maj'' find the collection date opposite the depth. 



Complete ecologic and natural history notes are difficult to make 

 on a large number of species before positive identifications are avail- 

 able. Such notes as are available are included under the appropriate 

 genera or species in the systematic section below. Egg capsules of 

 the gastropods were turned over to Dr. Gunnar Thorson of 

 Copenhagen for study and the results of his work are now ready 

 for publication. 



The Molluscan Fauna op Point Barrow 



Table 2 summarizes the geographic distribution of the Point Barrow 

 mollusks, as well as their distribution in depth at Point Barrow. 

 It should be understood that both of these are subject to change 

 pending reexamination of collections and more extensive dredging at 

 Point Barrow. 



Among the prosobranchs of the gastropods there are 20 famOies, 

 comprising at least 35 genera and 70 species, plus at least 10 varieties. 

 Ten of these families are represented by only one species. The largest 

 families are the Turridae, with 5 or more genera and 13 species, and the 

 Neptuneidae, with 6 genera and 11 species. The Lamellariidae and 

 Trochidae are next, each with 3 genera and 11 species. The genus 

 Buccinum, with 8 species, is by far the largest genus, the next largest 

 being Boreotrophon with 4 species and Trichotropis with 3 species. 



The identification of the Opisthobranchiata is still incomplete but 

 this group is being studied by Dr. H. Lemche of Copenhagen. When 

 his work is completed, several more eolids and dorids should be added 

 to the above list. 



At this point mention should no doubt be made of the mollusks taken 

 through the ice in winter. Dredging stations 49-51 were outside the 

 pressure ridge or point where the ice was grounded. One of the 

 5 living specimens of Admete couthouyi was taken at 162 feet, 2 of 

 the 7 living Oenopota harpa were dredged at 149 and 162 feet, and 1 of 

 the 5 living Beringius stimpmni was dredged at 162 feet. One of the 

 2 living Cylichna occulta was taken through the ice at a depth of 33 feet. 



It is of especial interest that more than half the living Buccinum 

 angulosum collected were taken by traps : 1 of the 5 typical B. angulo- 

 sum. (at 64 feet), 12 of the 18 var. normale (at 37 feet), 13 of the 26 var. 

 suhcostaium (at 37 and 64 feet), and 13 of the 14 var. transliratum (at 

 37, 64, and 80 feet). Several other species of Buccinum were also 

 taken with traps: 5 of 9 J5. polare (at 64 and 80 feet), 2 of 10 5. tenue 

 (at 64 and 80 feet), 1 of 40 B. plectrum (at 37 feet), and 1 of 50 B. 

 gldciale (at 80 feet). 



