6 A Canadian Arctic Expedition, 1913-18 



in 9 and 10. Ovaries and oviducts are paired in 11 and 12; spermathecae are 

 present on one side of 12-14, and on the other side there are vestiges of sper- 

 mathecal ducts in 11-14. The diameter of these specimens is but 0-5 - 0-55 

 mm. which is but half of that of the mature individuals of L. variegatus in the 

 same collections. 



Distribution and Systematic Relationships. 



DisTEiBUTiON.— L. variegatus has long been known from various parts of 

 Europfe. Eisen (1879:11) reported specimens from several localities in western 

 arctic Siberia as doubtfully belonging to this species. His figures and description 

 of certain " glands " in 9-12 make it probable that he was really dealing with 

 the spermathecae in L. variegatus. In an earlier paper Eisen (1872:122) also 

 records the species in Greenland, but this is regarded by some subsequent 

 writers as doubtful. It is now shown to have an extensive distribution in the 

 northern fringe of the continental areas of Eurasia and North America and 

 probably the area occupied by it is fairly continuous. 



L. inconstans has previously been known only from the North Central and 

 Great Lakes regions of the United States, and the new records greatly extend 

 its range. 



Systematic.-^L. variegatus has had an especially prominent place in the 

 oligochaetological literature of Europe, and is well known, not only to the 

 systematists, but also to students of regeneration phenomena and the related 

 morphological problems. Although it was known to Bonnet in 1745 and was 

 formally described and named by 0. F. Mtiller in 1774, yet it was not until 

 1907 that an adequate treatment of the reproductive organs appeared, when 

 Mrazek published his paper giving the results of an examination of something 

 over 200 sexually mature specimens. Such individuals are extremely rare and 

 the reproductive system is extraordinarily variable, and, in consequence, earlier 

 writers with not more than one to three specimens each had published more 

 or less discordant accounts. These discrepancies are easily explained in the 

 light of Mrazek's results. 



The atria are found in one or more of somites 6-11. There is sometimes 

 a single atrium, sometimes a pair, and sometimes either two or three atria 

 asymmetrically disposed. In the latter case the atrial somites are sometimes 

 not consecutive. The paired relation is the most common, and 8 is most fre- 

 quently the atrial somite. Aside from 8, somite 7 is the one more commonly 

 involved. The number of spermiducal funnels varies from a single one to three 

 pairs, with the presence of a single one or a single pair in 8 occurring most 

 frequently. Asymmetry in the arrangement of the spermiducal funnels is of 

 frequent occurrence. Similar irregularities in the number and arrangement 

 of spermaries, ovaries, and oviducts are found; the most common condition is 

 one pair of spermaries in 8 and one pair each of ovaries and of oviducts in 9. 

 An additional pair of ovaries and of oviducts in 10 is also of frequent occurrence. 

 There is most surprising variability in the number and arrangement of the 

 spermathecae. There were none of somites 7-17 that did not contain, sper- 

 mathecae in some one or more of Mrazek's series of worms. It is very common 

 to have two or even three spermathecae on one side of a single somite with the 

 result that as many as five and even six spermathecae in a single somite have 

 been found. The total number of these organs in one individual has been fojind 

 varying from three in one specimen to twenty-seven in another, and the number 

 of somites containing spermathecae has varied from two to nine. In nearly all 

 specimens, 10, 11, and 12 are found to contain spermathecae, and also in quite' 

 a large number, 9 or 13 or both have these organs, while they are found in any 

 of the other somites far less frequently. 



