ISA 



Canadian Arctic Expedition, 1913-18 



DISTRIBUTION OF ENCHYTRAEIDAE. The enchytraeid collections on which 

 this report is based are of particular interest because of the fact that nothing 

 has hitherto been known concerning this group in the region visited by the 

 Expedition. In fact, the entire arctic portion of the North American continent 

 is practically unknown territory with ivgnrd to this group of animals, although, 

 as will be mentioned later, there is reason to believe that it is abundantly 

 represented there. Eisen (1872 : 122-123) reported Lumbricillus profugus 

 (Eisen), under the name Enchytraeus pagenstecheri Ratzel, from Godhavn, Green- 

 land. According to Michaelsen (1900 : 82), 0. Fabricius (1870) reported 

 Lumbricillus minutus (Mull.), under the name Lumbricus minutus, from Green- 

 land, but the exact locality was apparently not given. Ude (1896: 27) recorded 

 the occurrence of Enchytraeus albidus Henle (Enchytraeus vejdovskyi Eisen) at 

 Karajak, Greenland. Emery (1898), Moore (1899), and Welch (1917b) made 

 studies on Mesenchytraeus solifugus (Emery) collected in Alaska on and in Ihe 

 general vicinity of Mount St. Elias. Eisen (1905) studied the collections of 

 the Harriman Alaska Expedition on the west coast of Alaska, the vicinity of 

 Port Clarence being the northern limit. No other records occur in the literal u re, 

 and it thus appears that the Canadian Arctic Expedition collections present the 

 first indications of the enchytraeid fauna existing in the vast territory between 

 the west coast of Greenland and Bering strait. 



It will be noted that the representatives of the genus Henlea comprise a 

 considerable part of the collections. Ude (1901 : 19) has already pointed out 

 that Henlea is especially well represented in the arctic region. The other genera 

 appearing in the Canadian Arctic Expedition collections are also known from 

 other "parts of the far north. The common occurrence of Mesenchytraeus in 

 the high latitudes has been pointed out by Ude (1901 : 23), and on the snow- 

 fields and glaciers of high altitudes by Emery (1898), Moore (1899), and Welch 

 (1916 : 1917b). 



The arctic Canadian enchytraeid fauna, as indicated by the collections of 

 the Canadian Arctic Expedition, shows a similarity to that of arctic Europe 

 and Asia which is worthy of special mention. As nearly as specific identifica- 

 tions have been possible, all of the species represented by sexually mature 

 material, exclusive of new forms, are known from arctic Eurasia, four having 

 been originally described from that region. Two species (Henlea nasuta and 

 Lumbricillus lineatus) are apparently cosmopolitan. 



While the list of enchytraeids taken by this Expedition is not extensive, 

 and while the collections were not made in an exhaustive manner, the results 

 confirm previous conclusions concerning the geographical relations of this family, 

 viz., that the group is preeminently northern in its distribution. Such Arctic 

 regions as have been examined yield evidence of a rich enchytraeid fauna. 

 The abundance of some of these worms reported by earlier collectors is an 

 indication of their successful adjustment to the rigid conditions of the environ- 

 ment. There is every indication that future collections will show the Enchy- 

 traeidae to be one of the most prominent and most widely distributed of the 

 groups of animals occupying the north frigid zone. 



