Trematodes and Cestodes of the Canadian Arctic Expedition, 



1913-18. 



A. R. COOPER. 



(With two plates.) 



INTRODUCTION. 



The trematodan and cestodan fauna of the Arctic regions has received not 

 a little attention from investigators up to date, but only a comparatively small 

 amount of material has been collected from that part of the area bordering on 

 the North American continent. It is to Fabricius (1780), who investigated 

 the first of this material which was obtained in Greenland, that we must go for 

 the earliest descriptions of many of our species. Krabbe (1865) studied the 

 avian cestodes in particular and described many species also from Greenland. 

 Zurn (1874) and Comini (1887) dealt with material collected by two polar 

 expeditions and Bergendal (1892) investigated to a certain extent the parasitic 

 fauna of Northern Greenland. , But the latest and most important papers are 

 those by Zschokke (1903), Linstow (1905) and Odhner (1905). Zschokke and 

 Odhner studied the cestodes and trematodes, respectively, obtained by the 

 German Expedition of 1898 to Spitzbergen and the neighbouring islands of the 

 Arctic ocean, and Linstow, the nematodes, acanthocephala and cestodes collected 

 by the Russian Polar Expedition of 1900 to 1903. 



So far as I am aware the parasitic fauna of the Arctic coasts of Eastern 

 Siberia, Alaska and Canada has not up to the present been investigated, but the 

 collections made by the Canadian Arctic Expedition, in so far as they have 

 already been reported upon, show that the region is rich in new forms and 

 worthy of further extensive study. 



MATERIAL. 



The material, which was all obtained by Mr. Frits Johansen, consists of 

 one species of trematode only and sixteen species of cestodes. The latter include 

 four considered to be new, one belonging to the genus Aploparaksis which was 

 not determined with certainty specifically, and two larval members of the genus 

 Diphyllobothrium. To this there are addied one species of ectoparasitic trema- 

 tode, namely, Epibdella hippoglossi, which were collected by Mr. C. H. Young, 

 and one of cestode, Abothrium rugosum, collected by Mr. Johansen in Nova 

 Scotia. It is thought that since they were also found by Fabricius in Greenland 

 and by Linstow in the European portion of the Arctic Ocean, respectively, and 

 consequently belong to the Arctic fauna, they might well be included here. The 

 writer has some new data on one of them in particular to submit. The trema- 

 todes and cestodes are dealt with together in this paper on account of the small 

 number of the former. The following table shows their distribution as regards 

 hosts, localities and dates: 



9133-1* 



