496 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
uncommon in the New England region and extends its range only into 
the northern part of it. It is nearly circumpolar in distribution (Redi- 
korzew, 1908b, p. 12) being recorded from the coast of Norway, Spitz- 
Text-flg. 13.- 
X 16. 
Caesira crystallina (Moller). Part of right side of branchial sac. 
bergen, between Bear Island and Hope Island, Franz Josef Land, 
Barents Sea, Murman Coast, White Sea, Siberian Arctic Ocean, 
Davis Straits, Cape Arton, Greenland, and Iceland, and attains in 
some of these localities a much larger size than the specimens above 
described. Redikorzew (1908b, p. 12) says, "It prefers a stony 
bottom, but occurs also on sandy and muddy bottoms ranging from 
10 to 180 meters." He describes in the same article (p. 13) a variety 
(tubcrculata) from the New Hebrides Islands (11-26 meters). 
