576 F- A. Potts, 



of Nanaimo, Vancouver Island in August, 1911. A Single shrimp 

 of the species Crangon communis Rathb. was noticed, to tlie ventral 

 surface of whicli was attached a pale yellow fungus-like body 

 fring-ed witli numberless lobes and so wide as to impede the action 

 of the abdominal appendages. Exaniination in the laboratoiy showed 

 at once the presence of characteristic Cirripede larvae and it became 

 quite clear that this was a new or little known Rhizocephalan. 

 Even more curious than the external appearance was tlie internal 

 structure revealed by a minute study of the animal and I hasten 

 to record such facts of structure and biology as could be ascertained 

 from this Single specimen. It was fixed in corrosive-sublimate Solution 

 with acetic acid as soon as a cursory exaniination of the living animal 

 had been made. On arrival at Cambridge careful drawings of the 

 external appearance were made and tlien a complete series of sections 

 was cut. From their study it was possible to reconstruct a great 

 deal of the structure of the animal. 



I should like to take this opportunity of acknowledging my 

 indebtedness to the Cauadian Government who maintain the Biological 

 Station at Departure Bay, Nanaimo, British Columbia, to the members 

 of the Controlling Biological Committee who arranged that I should 

 be allowed to take advantage of its facilities and to the Director, 

 the Rev. G. W. Taylor, for his personal kindness to me. 



The Host. 



Crangon communis Rathbun. 



The following notes of the distribution of this shrimp are taken 

 from Miss Rathbun's account of the Crustacea in the Harriman 

 Expedition Reports. 



^'■Crangon communis Rathbun, The Für Seals and Furseal Islands 

 of the North Pacific Ocean 1899 Pt. 3 p. 556. 



Distribution. From Bering Sea to San Diego in California 

 (including Puget Sound and Straits of Fuca), 20—309 fathoms, taken 

 at 142 stations by the Albatross offen in large numbers. Less 

 abundant at southern localities. Otf southeastern coast of Kamchatka, 

 96—100 fathoms, at two Albatross stations." 



My own specimen was taken between Newcastle Island and 

 the Five Fingers Rocks, close to the mouth of Departure Bay, 

 Vancouver Island, at a depth of about 15 fathom on a rocky bottom. 

 Examples of this grey shrimp were not infrequent in the dredge, 

 but not more than 20—30 passed under my Observation altogether. 



