Oligochaeta 7 A 



L. inconstans, like its congener, is very rarely found sexually mature and 

 the few specimens thus far obtained in that condition indicate that in this 

 species also, there is much variability in the number and arrangement of the 

 various reproductive organs. The most characteristic difference" between the 

 two species is in the general location of these organs and in the number 

 of spermaries and spermiducal funnels. Paired atria, spermaries, and 

 spermiducal funnels in 10, with an additional pair of spermaries and sper- 

 miducal funnels in 9, is the usual condition in L. inconstans, while a single pair 

 of atria and of spermaries in 8, and a single spermiducal funnel or a pair in that 

 somite is the usual condition in L. variegatus. The spermathecae of L. inconstans 

 are normally about two somites farther posterior than are those of the other 

 species. Size is not ordinarily very significant as a distinguishing character, 

 but no specimen of L. inconstans has been found with a diameter much more 

 than half of that of ordinary mature specimens of L. variegatus, and now a similar 

 difference is apparent between mature specimens of the two species when found 

 in the same situation. This is true in each of the two collections of the expedition 

 in which L. inconstans is contained. 



Unfortunately there has been no series of sexually mature specimens of L 

 inconstans at all comparable in numbers with that of the European specie^ 

 obtained by Mrazek. Including the single specimen to which reference was 

 made by Moore (1906 : 169), we know the position of the atria in but eleven j 

 and of the spermathecae in but five specimens of L. inconstans from the Great 

 Lakes region of North America. The atria are paired in 9 in two specimens; 

 paired in 10 in eight specimens; and paired in 11 in one. In each of the two 

 with atria paired in 9 there are spermaries and spermiducal funnels in 9 ; ovaries 

 and oviducts in 10 and 11; one has spermathecae in 11-15, in part asymmetrical, 

 and in the other they are undeveloped. In the specimen with the atria paired 

 in 11, there are paired spermaries and spermiducal funnels in 9, 10, and 11; 

 a pair of ovaries and oviducts in 12; and spermathecae in 12-16, in part asymme- 

 trical. In two earlier papers (1895 and 1905) I have referred to this specimen 

 with atria in 11, and included it with others in a statement that spermaries are 

 present in 9 and 10 and ovaries in 11 and 12. A re-examination of this specimen, 

 with greater experience in interpreting vestigial structures in these worms, 

 has convinced me that in this particular individual, the gonads and ducts of 

 11 are in reality spermaries and spermiducal rather than ovaries and oviducal 

 as previously announced. Vestiges of the funnels is about all that is present 

 to represent the ducts, and their position indicates that they probably are 

 spermiducal structures. In each of the eight specimens with paired atria in 

 10 there are paired gonads, presumably spermaries, in 9 and 10; and five of 

 them have at least traces of spermiducal funnels in 9 and 10. In the others, 

 recognizable traces of the funnels are lacking. Ovaries and oviducal funnels 

 are present in 11 and 12 in each of five of these eight specimens; two others 

 have gonads, presumably ovaries, in 11 and 12, but no. recognizable funnels; 

 and one has one pair of ovaries and a pair of oviducal funnels in 11, but none 

 in 12, except a rudimentary gonad on one side. Spermathecae are recognizable 

 in but five of the specimens and in some are somewhat asymmetrical, having 

 in some somites a single spermatheca instead of a pair. One specimen with 

 atria in 9 has spermathecae in 11-15; one with atria in 11 has spermathecae in 

 12-16; and of three specimens with atria in 10, one has spermathecae in 11-15, 

 one has them in 12-15, and one has them in 12-16. The specimen described 

 from arctic North America has them in 11-14. No two of the six specimens 

 which have the organs all present have an identical arrangement of them. 



In connection with the question of the possible identity of the two species 

 of Lumbriculus mentioned in this paper, it is interesting to note that in all of 

 Mrazek's series there were but three that had atria in 10, and each of these 

 had an asymmetrical arrangement of these organs, there being in each case 

 one or two atria in a more anterior somite. In at least one of the very small 



