60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 28 



Also, when possible, some of the animals were examined in an at- 

 tempt to determine their breeding season from the state of develop- 

 ment of the gonads. It was not feasible to try to fertilize the eggs as 

 they were all too often cooked or frozen, depending on the vagaries 

 of the refrigerator. 



Plankton samples were also kept in the refrigerator and, later, in 

 the reefer (a walk-in refrigerator), which prolonged the life of the 

 specimens, thereby allowing more time to work on them. 



DREDGING STATIONS AND COLLECTING DATA 

 ZONATION 



In general there are three types of bottom off Point Barrow. From 

 the shore out to a depth of lo to 20 feet there is gravel, which is con- 

 tinuous with the beach; 20 to about 100 feet, fine, blue, compact, 

 sticky mud; and beyond 100 feet, rubble, in which there may be 

 streaks of boulders, gravel (coarser than the beach gravel), or shell 

 (mainly Hiatella), and regions in which there are mixtures of some 

 or all of these. In general, the farther one proceeds ocean ward, the 

 less likelihood there is of boulder streaks, but there are stones of vary- 

 ing sizes everywhere. 



For miles out to sea there is an annual deposition of mud, the 

 amount depending on whether the ice stays near shore; when the 

 ice is "in" there is less shore erosion because there is less surf. In 

 1948 the bottom was free of mud beyond a depth of 100 feet, but in 

 October 1949 the entire ocean bottom offshore was covered with 3 

 or 4 inches of mud. 



These three regions have their respective faunas. In the gravel 

 along shore Rhizomolgida glohularis occurred in patches where the 

 sand had been segregated from the coarser gravel, and in places as 

 many as 50 pounds of this tunicate could be brought up in a single 

 dredge haul. Quantities of the washer-shaped bryozoan Alcyonidium 

 discifornie were also taken all along the gravel zone. These two were 

 by far the most abundant surface animals of this zone. An occasional 

 white dorid, probably Aldisa zctlandica, and certain annelids, such 

 as Phyllodoce groenlandica, were dredged. 



The animals living within the mud at the shoreward edge of the 

 mud zone encroached upon the gravel zone where the gravel was not 

 so thick as to close the burrows or allow them to collapse. Compara- 

 tively little is known of the animals living beneath the surface in the 

 mud zone, for sampling in that region is a tedious, time-consuming 

 process, but good collections were made of the surface and near- 



