8 A 



Canadian Arctic Expedition, 1913-18 



number of specimens in his series having atria in 11, there was evidence of 

 regeneration of anterior somites. This would be very likely to alter the number 

 of somites and hence the numerical relations of organ positions. 



Lumbriculus, sp. 



The collection contains two small specimens having data as follows: 

 'Brackish pond at Teller (Port Clarence), Alaska. In moss-brink. August 3, 

 1913." They apparently are sexually immature specimens of some species of 

 Lumbriculus. Sections of the most promising looking specimen revealed defective 

 preservation, some evidence of regeneration of a few anterior somites, and a lack 

 of reproductive organs except apparent traces of gonads. These latter are in 

 somites 10-13 and possibly in one side of 9. Because of the change in the number 

 of somites liable to occur in the process of regeneration, the location of the gonads 

 has little systematic significance, and there is insufficient basis for identification. 



The occurrence of representatives of Lurroriculidae in brackish water is at 

 least unusual. 



LITERATURE CITED, PART I. 



Eisen, G. 



1872. Om nagra arktiska Oligochseter. Ofv. Kongl. Vet. Akad. Forh. 29 : 119124. 



1879. On the Oligochaeta collected during the Swedish Expeditions to the arctic regions in 

 the years 1870, 1875 and 1876. Kongl. Sv. Vet. Akad. Handl. 15 : 149. 



Moore, J. P. 



1906. Hirudinea and Oligochaeta collected in the Great Lakes Region. Bull. Bur. Fisheries 



25 : 153171. 



Mrazek, Al. 



1907. Die Geschlechtsverhaltnisse und die Geschlechtsorgane von Lumbriculus variegatus 



Gr. Zool. Jahrb. Anat. u. Ont. 23 : 381462. 



Smith, F. 



1895. Notes on Species of North American Oligochseta. Bull. III. State Lab. Nat. Hist. 

 4 : 285297. 



1905. Notes on Species of North American Oligochaeta. V. The Systematic Relationships 

 of Lumbriculus (Thinodrilus) inconstans (Smith). Bull. 111. State Lab. Nat. 

 Hist. 7 : 45 51. 



