16 JAMES A. GRIEG. [2nd ARC. EXP. fram 



July 30, 1900. Mouth of Stor Valley. 



Aug. 1, 1900. — „ — — ; up to 20 m. Small stones and 



some clay. 



Aug. 1, 1900. Mouth of Stor Valley; 60—4 m. Small stones. 



Aug. 4, 1900. Sjopolse Ness, 50—30 m. 



July 8, 1901. Ren Bay. 



July 12, 1901. Bay at Land's End. 



Aug. 3&4, 1902. North of the peninsula, Gaasefjord; about 108 m. 



The disc in the largest specimens has a diameter of 28 mm. 



In "Echinoderms from East Greenland", Mortensen (28, p. 83) points 

 out that a large number of Ophiura sarsi from Jan Mayen, are 

 all of one size, the diameter of the disc being from 15 to 20 mm. 

 They must thus all belong to the same year. The specimens col- 

 lected by the "Varingen" and the "Michael Sars" also show that all the 

 ophiuroids occurring in one locality are of the same size, and therefore 

 of the same age. It appears to be quite an exception when specimens 

 of two, or possibly three, ages occur in one locality (Grieg, 14, p. 21). 

 Vanhoffen (85, p. 239) has also observed that the Ophiura sarsi 

 occurring in one locality are all of the same size. He thinks, however, 

 that the fact of large and small specimens not being found together, is 

 due to the greater concealment of the latter. My specimens, however, 

 do not confirm this view. The Fram Expedition collection, like those 

 of the "Voringen", the "Belgica" and the "Michael Sars", shows that all 

 the specimens taken in one locaHly are as a rule of the same size, 

 although sometimes individuals of two different ages may be found in 

 the same locality. At a station in Gaase Fjord, for instance, the disc 

 in most of the specimens measured from 19 to 23 mm. in diameter, 

 while one was only 8.5 mm. The specimens from Ren Bay are mostly 

 of two diameters — 14 or 15 mm., and 20 or 21 mm. The above 

 remarks concerning Ophiura sarsi appear also to be applicable to the 

 other arctic ophiuroids. 



Another ophiuroid was taken in a bay near Land's End together 

 with a typical Ophiura sarsi. It had poorly-developed arm-combs, no 

 papillae on the bursal slits, and three brachial spines of equal length, 

 that were no longer than the lateral plates of the arms (PI. 1, figs. 6-8). 

 It is especially in this last character that the specimen differs from the 

 typical Ophiura sarsi, and more resembles Ophiura albida, whose 

 brachial spines, however, are not more than half as long as the lateral 

 plates. The specimen differs moreover from Ophiura albida in having 



