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BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



VOLUME 1 



TABLE 11. Relation between P 2 and P 3 in 16 specimens of Heliometra, several arms of the last three having 



been examined 



[From Grieg, 1904, p. 16.] 



Length ratio, P 3 /Pj 



0.6 0.5 0.6 0.7 0.6 0.6 0.6 0.6 0.8 0.6 0.6 0.7 0.5 



Michael Sars, 1901, Sta. 87 



from 1:0.83 to 1:1.08; and in a third, of which three arms were measured, from 1:0.69 

 to 1:1.19. On two arms of one of the specimens from Vtfringen station 374 the rela- 

 tionship was 1:0.95 and 1:1.16. 



Grieg finds that the IBr series of quadrata also differ somewhat from those of 

 glacialis, though here again intergrades occur. 



The genital pinnules in typical glacialis are relatively shorter and more robust than 

 in quadrata, though not more so than can be accounted for through difference in age in 

 the individuals concerned. 



Grieg came to the final conclusion that Levinsen (18S6) was correct in considering 

 quadrata as a synonym of glacialis. 



Doderlein says that quadrata can scarcely be maintained even as a variety of 

 glacialis, with which it agrees in its geographical distribution. The Helgoland collection 

 which he studied contained a large number of specimens from eastern Spitzbergen with 

 an arm length of from 30 to 170 mm. The largest showed indubitably the characters 

 of typical glacialis; the characters of the smallest are rather indefinite ; those of medium 

 size, with an arm length of about 100 mm. show in part more or less clearly the characters 

 of quadrata, while others may be clearly recognized as glacialis. The strangest thing 



