ARCTIC SEA TO THE WEST OF GREENLAND. 31 



Verrill has described * a variety under the name of nitida, taken at Eastport, Maine, 

 at low water, but which, in his opinion, presents no peculiarities which may not 

 be considered due to increased age. The specimen is remarkable for its large size 

 (4 inches in diameter) and regular form. The rays are equal, and the median row of 

 plates quite distinct. The lateral spines are four or five in number, in a transverse 

 row, those nearest the ambulacra being longest. The adambulacral plates bear two, 

 three, or sometimes four long, tapering, and rather slender spines. The dorsal plates 

 are crowned by eight to twelve small, somewhat radiating spines, thicker and more 

 obtuse than those of the ordinary variety. The papulae are not very numerous, rather 

 large, and occur mostly in pairs. Suckers numerous and much crowded, in four 

 rows. 



Judging from the description alone of a single specimen, it would be difficult to 

 say whether the modifications above noted possess any greater significance than mere 

 conditions of growth. Augmentation in the number of ambulacral and lateral spines, 

 as well as of those upon the ossicles of the disk, greater development of the median 

 row, increase in the number of papulae, and crowding and increase of the ambulacral 

 suckers, are, it is true, changes that accompany structural growth ; still, if we are 

 only to give these characters such a value in the present case, it seems strange that the 

 form in question is not of more frequent occurrence in localities where Stichaster 

 albulus may be taken in the utmost abundance. 



A single large example which may be referred to this variety was dredged at 

 Proven during the outward journey of Capt. Nares's Arctic Expedition, the diameters 

 of the rays and disk being respectively 30 millims. and 6 millims. 



Comparing specimens from the coast of Maine with those from Franklin-Pierce 

 Bay (lat. 79 25' N.), we have detected no remarkable difference ; and Mr. Verrill records 

 the same conclusions in regard to specimens from Greenland which he had studied. 



Distribution. 



a. Northward of Smith Sound : Franklin-Pierce Bay, lat. 79 25' N., 15 fms. 

 (Nares's Exped.), the most northern locality on record. 



In Davis Strait : Godhavn Harbour and Holsteinborg (' Valorous ' Exped.) ; 

 Proven, 13 fms. (Nares's Exped.}. 



b. North of American Continent : Grand Manan (Stimpson) ; Eastport, Maine 

 (Verrill). 



c. North of European Continent: Spitzbergen (Liltken) ; Iceland, Ofjord (Lutken). 



Description of the Illustrations of this Species on Plate II. 



Fig. 13. Abactinal aspect of the animal : natural size. 



14. A larger and almost equal-rayed variety from Proven. 



* Proceed. Boston Soc. Nat. Hist. vol. x. p. 351. 



