ARCTIC SEA TO THE WEST OF GREENLAND. 43 



bottom rocky with rounded pebbles. This example is nine-armed, and measures 14 

 millims. across its greatest diameter, R=7 millims., r=3 millims., the length of the 

 arm from the tip to the arm-angle being rather less than 4 millims. The ventro-lateral 

 series of paxillse are about twelve in number on each side of the ray and quite marginal, 

 instead of being entirely on the ventral surface as in older forms. There are about 

 twenty of the transverse " ambulacral " combs between the extremity of the ray and the 

 mouth-plate, each composed of four spines. Each mouth-plate carries four spines on 

 its margin, which gives eight to the mouth-angle, and there are about two or three of 

 the inner secondary series present. The dorsal paxillae upon the disk are composed of 

 four to six spinelets, but those on the rays have seldom more than three. 



Variations. This species on the whole would seem to be very fairly constant in 

 character, although considerable variation is manifest in the number of rays. Brandt * 

 notes a ten-armed variety from Sitcha ; and seven-, eight-, and nine-armed forms are cited 

 by Liitken. The last-named observer also records a variety, taken in Iceland, Floroen, 

 and Greenland f, in which the rays are blunter and coarser, as well as more uniform in 

 thickness throughout their length, and in which the paxillae of the ventral interbrachial 

 spaces are more compressed and carry a greater number of spinelets (10-20). With our 

 present information, however, it is difficult to say what claim these modifications 

 have upon our recognition. 



Distribution. 



a. Greenland: up tolat. 70 N., Omenak (Lutkeri), being the most northern locality 

 on record ; Davis Straits, lat. 67 -50' N., long. 55 27' W., 20 fms., bottom of broken 

 barnacles and shells (' Valorous ' Exped.) ; lat. 65 N., 30 fms., rocky bottom (Nares's 

 Exped.). 



b. North of American Continent : Newfoundland (Liitken) ; St. George's Bank, 

 25 fms. (Verrill) ; Grand Manan (Stimpson); Fundy Bay and Maine, low-water mark 

 down to 20 fms. (Verrill). 



c. North of European Continent: Finmark, Tromso (Liltken); Iceland (Liitken); 

 Fa?roe Islands ; British Isles to S. of Ireland and the Channel. 



d. Sitcha (Brandt). 



Description of the Illustrations of this Species on Plate III. 



Fig. 5. Abactinal aspect of the animal : natural size. 



6. Actinal aspect of the same specimen: natural size. 



7. Portion near the middle of a ray, actinal aspect : magnified. 



8. Portion near the middle of a ray, abactinal aspect : magnified. 



LOPIIASTEB PUECIPER (Diiben & Koren), Verrill. Plate III, Figs. 9-12. 



1844. Chcetaster borealis, Diiben, (Efv. Kongl. Vet.-Akad. Forhandl. 1844, p. 113. 



1844. Solaater furcifer, Diihen & Koren, Kongl. Vet.-Akad. Handl. 1S44, p. 243, pi. vi. figs. 7-10. 



1862. Solaster furcifer, Dujardiu & Hupe, Hist. Nat. Zooph. Eohinodernies, p. 355. 



1878. Lophaster furcifer, Verrill, Amer. Journ. Sci. & Arts, ser. 3, vol. xvi. p. 214. 



* Prodr. Descrip. animalium &c. p. 71. t Vidensk. Jleddelelser for 1857, p. 38. 



