1898-1902. No 13.] ECHINODERMATA. 23 



Tlius ill this specimen the proportion of the disc-diameter to the length 

 of the arm is as 1:2, while in Gorgonocephalus eucnemis it is from 

 1 : 2.43 to 1 : 1.43. The proportion of the thickness of the arm to the 

 diameter of the disc is as 1 : 8.67 in Gorgonocephalus agassisi, in the 

 other species from 1 : 5.8 to 1 : 7.67. This is in harmony with what 

 DoDERLEiN (7, p. 227) found, namely that Gorgonocephalus agassizi 

 has comparatively longer and more slender arms than the other Scandi- 

 navian and arctic Gorgonocephali. In young specimens, however, this differ- 

 ence is less striking (see Michailovskij, 26, p. 497; 27, p. 174). Individual 

 variation, however, is here very marked. In one Gorgonocephalus 

 eucnemis, measuring 46 mm. in diameter, the proportion of the disc- 

 diameter to the length of the arm as far as the 5th ramification, was as 

 1 : 1.43, and that of the thickness of the arm between the 1st and 2nd 

 ramifications and the diameter of the disc, as 1 : 7.67. In the specimen 

 measuring 47 mm., on the other hand, these proportions are respectively 

 1 : 1.68 and 1 : 5.87. In like manner the arms may vary in length 

 and thickness in the same individual. In a specimen measuring 32 mm., 

 the proportion of the disc-diameter to the length of one arm to the 

 fifth ramification, is as 1:2.06, of another arm as 1:2.19; and the 

 proportion of the thickness of the same arms, between the 1st and 

 2nd ramifications, to the diameter of the disc, is respectively 1 : 7.11 

 and 1 : 6.4. 



The specimen from Sjopolse Ness differs from the others in having 

 a smooth, naked skin. In the other specimens, the ribs, at any rate, 

 are covered with granulae. 



Gorgonocephalus agassizi, Stimpson. 

 Locality. 

 Aug. 4, 1900. SJ0p0lse Ness; 30—50 m. Small stones. One specimen. 



Echinoidea,. 

 Strongylocentrotus drebachiensis, 0. F. Mijller. 

 Locality. 

 July 29, 1898. The harbour, Egedes Minde. 

 Aug. 4, 1898. The harbour, Upernivik; 26—6 m. 

 Aug. 18, 1898. Bay in Rice Strait. 

 Aug. 24, 1898. Rice Strait; 40—8 m. 



