EXPLAXATION OK PlATE 7 



Figs. 1, 2. — Boreutrophoii clathralus (Linnaeus): 1, from 110 feci (USXM 606203); 2, from 



125 feci. 

 Fig. 3. — Boreotraphun clathratus var. scalariforinis Gould from 184 feet, showing llie more 



promincnl varices, which, because of chipping, always appear roughly crenulate. 

 Figs. 4-7. — Boreoirophon clathratus var. gunneri Loven: 4, from 453 feet; 5, from 152 feet; 



6, from 741 feet (shown with its operculum); 7, from 125 feet. These specimens show 



a varying number of varices and varying degrees of angularity at the shoulder. 

 Figs. 8-10. — Boreotrophon truncatus (Str0m), var..-" from 125, 152, and 152 feet, respective!}-. 



Specimens shown in 8 and 9 have a longer canal than typical truncatus. 

 Figs. 11, \2.— Boreotrophon beringi (Dall): 11, washed ashore Sept. 20, 1949; 12, from 453 



feet. 

 Figs. 13, 14. — Boreotrophon pacificus (Dall): 13, washed ashore Aug. 21. I'H'^: 14, from 132 



feet. 

 Magnification: All X 1.5. 



