Canadian Arctic Expedition, 1913-18 



the members of the expedition made their headquarters for a considerable period. 

 One lot of specimens was obtained from fish specimens talcen by Dr. R. M. 

 Anderson on the east shore of Banks peninsula, Bathurst inlet, Northwest Terri- 

 tories. The collection comprises nine lots of specin^ens from six host species, 

 each lot including from a few to numerous individuals and representing, in some 

 instances, several host individuals. Three species of fresh-water fishes, two 

 marine fishes, and one bird constitute the entire list of acanthocephalan hosts 

 recorded by the expedition. In all, these harboured four species of Acanthoce- 

 phala. Echinorhynchus salvelini and E. coregoni are characteristic species from 

 North American fresh-water fishes, though the present records greatly extend 

 the known geographical range of both. Echinorhynchus gadi, the only species 

 found in marine fishes by the expedition, is a species common to marine hosts 

 of both Europe and America. A new species of the genus Filicollis from the 

 King Eider stands intermediate between the European and the North American 

 species of this genus, but in some respects shows much closer relationship with 

 the previously described American species. Data concerning these four species 

 are given in the following paragraphs. 



Filicollis arcticus, n. sp. 



(Plate I, Figs. 1 to 5). 

 Color: orange (Johansen's notes). 



Specific Diagnosis. — With the characters of the genus as emended by 

 Van Cleave, 1916. Body of fully mature individuals preserved in alcohol, 

 large, thick, approximately cylindrical in cross section, much folded or wrinkled, 

 especially in posterior region, due to contraction; about 20 mm. long and 5 mm. 

 in maximum diameter. Anterior portion of body wall covered with delicate 

 cuticular spines, visible only in cleared portions of the body-wall. Proboscis 

 ovoid, 0-77 mm. long, and 0-73 mm. in diameter, armed with twenty-two 

 longitudinal rows of seven or eight hooks each. Four or five hooks nearest 

 base of each row more delicate than those anterior to them and supplied with 

 less prominent roots. Anterior hooks provided with prominent posteriorly 

 projecting roots longer than the hook proper. Hooks range in length from 89 

 to 118 /x. Heavier hooks of anterior proboscis region are 35 ti thick at point 

 of emergence from proboscis wall, while those of posterior region range from 

 18 to 24 ^ thick. Neck approximately cylindrical, 1-2 mm. long by 0-44 mm. 

 in diameter. Proboscis receptacle inserted at base of proboscis and extending 

 through neck and into body cavity, entire length 2-.t mm. Embryos within 

 body cavity of gravid female 126 to 15.t ix long by 30 to 41 /x in diameter, most 

 frequent size about 150 by 41 ^x. 



Type host, King Eider, Somateria spectabiUs (Linnaeus), in intestine. 



Type locality, Bernard harbour, Northwest Territories, Canada. 



Collected by Mr.' F. Johansen, June 16, 1916. 



Cotypfs are deposited in the Victoria Memorial Museum, Ottawa, Canada, 

 and in the collection of the writer at Urbana, Illinois. 



The above species description is based upon the examination of four speci- 

 mens. In all of these the proboscis was completely retracted within the body. 

 The data concerning the proboscis and its associated structures such as the hooks 

 and the proboscis receptacle are from a single fully mature female from which 

 the writer dissected out the proboscis. This dissection was stained and cleared 

 in the usual manner and mounted as a permanent mount in damar. Portions 

 of the body wall of this same individual were in like manner cleared and mounted 

 to permit of a study of the body spines which are unrecognizable in surface 

 view of alcoholic specimens. These spines' recall those previously described 

 by the writer for Filicollis botulus in that in the gravid female they are very 

 poorly developed, appearing as very slight elevations of the cuticula in which 

 spines are observable only through close observation (see fig. 3). 



