NO. 9 MARINE INVERTEBRATES, ALASKA — MacGINITIE I29 



together — a phenomenon hitherto unknown in arrow worms. In the 

 laboratory some of the young, which were nearly 3 mm. long, began 

 escaping from the marsupium. 



This is said to be a bipolar, cosmopolitan species, restricted in 

 warmer seas to deeper water. In colder waters it may be found close 

 to the surface, but even in the Arctic it occurs mainly in deep water 

 (Kramp, 1938b; Dunbar, 1942b). 



Had it not been for the upwelling of deeper water, this species and 

 Sagitta maxima probably would not have been taken at Point Bar- 

 row, for even the cosmopolitan .S". maxima usually occurs only in the 

 deeper parts of the ocean, never less than 200 meters below the surface 

 in tropical and temperate regions (Kramp, 1938a). 



Phylum BRACHIOPODA 



Only two species of brachiopods were found. Dr. G. Arthur 

 Cooper, who identified these, will report on some noteworthy charac- 

 teristics of the smaller species in a future publication. 



Shells of Hemithyrus psittacea (Gmelin) were common, and liv- 

 ing specimens were occasionally brought up from depths of 120 to 

 741 feet. The hauls from 328, 295, and 453 feet yielded the greatest 

 numbers, 11, 6, and 12, respectively. Specimens from 20 to 22 mm. 

 in length appeared to be about 5 years old, and large ones were more 

 abundant than small ones. Specimens between 3.6 mm. and y.6 mm. 

 long were taken in September and October at depths of 328, 217, 477, 

 and 453 feet. Although this is a circumpolar, Arctic-Boreal species, 

 this is apparently the first record from Point Barrow. 



The smaller Diestothyris spitabergensis Davidson was taken at 

 depths of no to 741 feet, usually alive. In life the shell is tan. The 

 largest shells of this species were slightly over 15 mm. long, 12.9 mm. 

 wide, and 5.2 mm. in depth, and were from 3 to 5 years old. The hauls 

 from 150, 741, and 152 feet yielded 6, 5, and 7, respectively. The 

 greatest number, 13, was taken through the ice on February 18, 1950, 

 at a depth of 162 feet. Nine of these contained eggs, one contained 

 sperm, and in three the sex could not be determined without making 

 sections of the gonads. Nine of the eggs measured from 195 to 227 

 microns in diameter, with an average of 211 microns. Two small 

 specimens 3.6 mm. and 4.1 mm. long were taken from 477 and 741 

 feet, respectively. 



Phylum BRYOZOA 



The bryozoans, or moss animals, comprise an extremely important 

 part of the bottom fauna at Point Barrow and were found in large 



