ASTEKOIDEA OF NORTH PACDTC «iM> AI'.IMIVI WATEBB BTSH] 2 « 



dorsolateral Bpinelete are much Bmaller than the carinals and Buperomargrnali 

 iiuiv represent a ditincl forma ranging along (he Arctic shores of Asia. 



The st rui^rh t pedicellariae are rather tenderer and have less well-developed teeth 

 than have smur of the stout spiiictl berinijensis. They are mt\ Bcare abactinalrj in 

 the type series; but in larger examples from Plover Baj and Cape [isburne con- 

 spicuous Btraight pedicellariae of characteristic form are scattered here and there oyer 

 the dorsal surface. They are slender, incipiently toothed, and as long as the second- 

 ary spines. 



The largesl Arctic specimen, from Cape [isburne, has K 50 mm., and coarse 

 well spaced, strongly capitate, striate, unequal dorsal Bpinelets, 



The specimen from Nikolski, Bering Island, with K 39 mm., bae heavy, capitate. 

 Bubtruncate, abactinal Bpinelete and closely resembles the typical Antic form. The 

 marginal, actinal, and adambulacral spines arc rather more robust than in any of 



the Point Franklin examples. (PI. 14, fig. 4.) It is of interest to End that forma 

 arcticii extends so much farther south in the western part of Bering Sea than it • 

 in the oast. In the latter region it does not range south of latitude fit) . 



rorm« BKKIN<;KNSIS. new forma 



Plato 8, Figures 5/-5A; Plate 9, Figures I, 3, 4-6, 9-12; Plate 10, Figures 1, 3, 4; Plate 14, F.. 

 6, 6; Plate 15, Figures 2-5; Plate 10, Figures 2-6 



The bulk of the collection conies from the vicinity of the Pribilof Islands, from 

 Bristol Bay, from off the north coast of the adjacent Alaskan peninsula, and of 

 1'iiimak Island. Perhaps the most evident feature of these Bperamflna is that they 

 average much larger in size, although of course different growth stages are abundantly 

 represented Many of them have thick rays due usually to swollen gonads, although 

 in specimens from the same dredge haul there is much difference in the thicknec 

 the ra\ -. 



As a fair sample of the variations of specimens from the vicinity of the Pribilof 

 Islands, 20 examples from station 3536, 40 fathoms, may be taken. Two specimens, 

 each with It 58 nun., have r 11 and 12 nun., but the breadth of ray just beyond the 

 base is 16 or 17 mm., and 10 mm., respectively. The swelling in the latter fairly 

 extending toward the extremity. The abactinal spines are robust and have capitate. 



finely striated tiiis. There is much variation in the robustness and degree "f Bpacing 



of the spines. In one variety the spines are fewer and widely spaced. Counting 

 across the abactinal surface between the supcromarginal series of either side, there 

 may be only three series of major Bpines together with a few much '-mailer one-, or. 

 on another ray of the same specimen, seven series. In a more normal, slender-rayed 



example of approximately the same size there are in or 12 Spines aero— the ba-e 

 of the ray, but there is scarcely any arrangement in [ongiseries with the exception 

 of the irregular carinals where the spines are usually distinguished by their slightly 



in decidedly larger siae, and mote crowded position. The sparsely-spined variety 

 occurs at a Dumber of stations, a-. 3277, 3280, B291, 3293, 3294, 8297, 330J 

 axil... 3488, 8504, 3511. 



The marginal and actinal spine- BIS fairly typical and stand in regular series. 

 generally only one to a plate, but there is considerable variation in the details of 



