Il6 RATHBUN 



rostrum, too, is often intermediate between typical alaskensis and typical 

 alaskensis elongata. 



CRANGON SEPTEMSPINOSA Say. 



Crangon septemspinosiis SAY, Jour. Acad. Nat. Sci. Phila., i, 246, 1818. 

 Crangon crangon and Crangon -uulgaris of authors (part). 



Associated sometimes with C. alaskensis, which it closely resembles ; 

 it can be recognized at once by the rounded (non-carinated) abdominal 

 segments. In Alaskan specimens the antennal scale is a little more than 

 two thirds the length of the carapace ; it is equal to or 

 exceeds the distance from the gastric spine to the pos- 

 terior margin ; the extremity of the blade is obliquely 

 FIG. 55. Crangon subtruncate, slightly rounded, the antero-internal angle 



septemspinosa. Acicle J 



(x 2). station 323- retreating ; the spine surpasses the blade to a distance 

 exceeding the anterior width of the blade. The hands are variable in 

 length, being from three to three and one half times as long as wide ; 

 the obliquity of the terminal margin is as in C. alaskensis. All the ab- 

 dominal segments are free from carinae ; the sixth and seventh have a 

 slight median sulcus. 



There is considerable variability in Atlantic specimens of this species, 

 in the length both of the scale and of the hands ; I cannot see that our 

 Alaskan specimens differ essentially from those of Chesapeake Bay. 



Dimensions. Female, station 3230, length from tip of rostrum to tip 

 of telson 60.4 mm., length of carapace 15.6 mm., length of antennal 

 scale ii mm. 



Color. It is probable that in life the species could readily be detected 

 by the color markings. In alcohol the speckles of the dorsal surface 

 are more uniform and closer than in C. alaskensis, and the telson and 

 uropods are darker than in C. alaskensis from the same dredge haul. 



Distribution. This species is less abundant along the Alaskan coast 

 than C. alaskensis; it extends from the Arctic coast of Alaska at 

 Eschscholtz Bay southward along the eastern shore of Bering Sea to the 

 Shumagins ; the separate localities are as follows : 

 Chamisso Harbor, Eschscholtz Bay, 5-8 fathoms (W. H. Dall). 

 Port Clarence, in the seine, with C. alaskensis (W. H. Dall). 

 St. Michael, Norton Sound (L. M. Turner ; E. W. Nelson). 

 Head of Norton Sound, 5 fathoms (Point Barrow Expedition). 

 Off mouth of Yukon, 3^ fathoms (E. W. Nelson). 



Cape Etolin, Nunivak Island, anchorage, 8 fathoms, stony (W. H. Dall). 

 Hagemeister Strait, 8-15 fathoms, gravel (W. H. Dall). 

 Bristol Bay (C. L. McKay). 

 Bristol Bay, 3^ fathoms, with <7. alaskensis {Albatross station 3230). 



