150 GAMMA RID^, 



It was first taken by Holboll on the coast of Green- 

 land, from whence the great northern currents probably 

 drifted it to the shores of America : for, generally speak- 

 ing, the Crustacea of the eastern coast of America are 

 very distinct from those of the western coast of Eu- 

 rope ; and in instances where they may be found to be 

 identical, (as we believe to be the case with this species,) 

 they are essentially Arctic forms, which yield to the 

 opposite shore of each continent some few wandering 

 specimens. 



We have taken itwith the dredge from Plymouth Sound, 

 from which specimen our figure was drawn and described, 

 but the figure of the caudal appendages was drawn from 

 another specimen. Mr. Barlee has taken it while dredg- 

 ing in the Shetlands, as have also very lately the Rev. 

 A. M. Norman and Mr. J. Gwyn Jeffreys. The speci- 

 men which Stimpson describes as distinct, but which we 

 have incorporated with this species, was taken by him with 

 the dredge on coarse sandy bottoms, in the laminarian 

 and corralline zone on the coast of the Isle of Grand 

 Manan, U.S., North America. 



