;',t l.l l.I.ETIN 70, UNITED STATES NATIONAL MUSEUM 



Specimens of 1 u miilleri examined 



West coast of Swede. > Stanford University 



,,,„„ 6 Riksmuseum, Stockholm. 



Bohuslan (west coast Sweden) 9 Do - 



\\ udeguba HUM....,,.) — - 3 Riksmuseum, Stockholm 



(Sandeberg expedition). 



| I (Berufjord, 15 to 30 fathoms) 1 D °- 



Iceland (Reikiavik, 8 fa1 oms) l Do - 



of Bergen (90 to 200 fathoms) 5 Do. 



west of Nidingen (west coast Sweden) 1 Do. 



Specimens of L plasterias hyperborea examined 



Spitabergen (Ice Fjord) ! Riksmuseum, Stockholm. 



North ... Spitzbergen (80° 65' N., 11° 40' E., 16 fathoms) 4 Do. 



en (1 from Cross Bay; 2 fathoms) 2 Do. 



Baffin Bay (67° 59' N., 56° 33' W., OS fathoms) 3 Do. 



Remarks. There is do sharp line of demarkation between the two formae. 

 There is a considerable aumber of specimens which may be referred to either. In 

 Bering Sea north of about 60° the specimens are more like the Arctic race, although 

 larger as a rule. Even as far south as the Pribilof Islands (as station 3559) large 

 specimens resembling forma artica are found, but the crossed pedicellariae are larger 

 than in the typical form from the Arctic Ocean. (PI. 8, fig. be.) Occasionally (as 

 stations .'5290, 3600) well within the range of forma beringensis, specimens are found 

 which closely resemble forma arctica abactinally. If there is any geographic signifi- 

 cance to the large form from the southern part of Bering Sea, it is likely that these 

 southern "intermediates'' are simply variants of beringensis (especially as they have 

 the larger crossed pedicellariae), and not of the typical phase, found in the Arctic 

 Ocean. 



The variety from the Aleutian and Shumagin Islands is rather variable and not 

 typical bul is more like forma beringensis than arctica. A series of drawings of pedi- 

 cellariae on Plates 8 and 10 will show a real but slight difference between the northern 

 and southern forms. They are introduced also for comparison with the crossed 

 pedicellariae of L. hyperborea and L. »iii!leri. 



Through the interesl of Dr. T. Odhner, of the Naturhistoriska Riksmuseum, 

 Stockholm, 1 have received specimens of a number of Arctic species for comparison. 

 Especially useful have been the series of L. hyperborea and L. millleri. 



The question of whether these are distinct species or formae of the same species 

 has been frequently raised. Von Hofsten (1915, p. 62) has followed Grieg (1907, 

 p. 13) in considering them separate. The matter is of interest in determining the 

 nearest relative of arctica in the North Atlantic and adjacent Arctic Ocean. Grieg 

 (1907) writes: 



If we compare Asterias hyperborea with Asterias mulleri and nearly allied forms, we shall find 

 that it has quite a different and coarser armature on the abactinal face of the disk. The most 

 characteristic difference, however, pedicellariae. In Asterias mulleri there are a few 



forficifonn t] pedicellariae on the ambulacra] papillae, or they are altogether wanting; in 



on the other hand, the pedicellariae are forcipiform [crossed] and arranged in 

 tr. .ups. 



