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Show 168 MR. F. E. BEDDARD ON W O R M S [Feb. 16, should conclude that this species is one whose characters are not yet definitely fixed ; it is evidently on the way to entirely losing the setae upon the clitellum. The genital papillce, as has been already remarked, differ in the three individuals. In a there is, in the first place, a median sucker-like papilla upon segment vii., just in front of the circle of setae ; and in the second place, a single median papilla occupying an exactly corresponding position upon segment xviii. In b there is no anterior papilla or papillae ; on segment xviii. are two papilla? placed on the inner side of each atrial pore and lying below the circle of setae; the innermost papilla on each side is below as well as to the inside of the outermost, which occupies a corresponding position with regard to the male pore. In c the arrangement is by far the most complicated, and yet this individual is the one which has the most setae upon the clitellum. There are no anterior papilla,; on the eighteenth segment a small circular papilla lies above each atrial pore and another lies exactly below it, on the boundary-line between segments xviii./xix. In the middle of segment xviii. are two papillae lying side by side and above the setae of that segment. On the right-hand side of the body is another papilla, which lies just above one of these two. There are thus seven papillae in all. In all three individuals the atrial pores are lateral in position, being separated by the entire diameter of the body, which is here a trifle wider than either anteriorly or posteriorly. With regard to the internal anatomy, all three specimens showed the following characters in common :- The gizzard occupies the usual position, and there are a pair of intestinal cceca. The intestine has a small typhlosole. The atria have an extensively developed glandular portion, which extends from segments xvii.-xxi. in b and from xviii.-xxii. in a ; it is rather smaller in c, but then the worm itself is smaller \ I found two pairs of egg-sacs attached to the posterior face of the septa dividing segments xii./xiii. and xiii./xiv. ; they are pear-shaped with a long stalk, and not very wide at the widest end. The position and number of the spermathecce differ in the three individuals : in a there were two pairs somewhat unsymmetrically disposed; they open, however, in the intersegmental grooves v./vi. and vi./vii. In segment vi. lie a pair, of which one was very small and immature; the fully developed spermatheca consists of an oval pouch terminating in a narrow duct, from which arises a long cylindrical appendix. In segment vii. the spermatheca of the right side of the body had the same characters; on the left side the duct of the spermatheca, although opening in the normal position, is greatly elongated, traversing septum vii./viii. and expanding in the viiith segment into the large oval pouch. The diverticulum of this spermatheca lies in segment vi. 1 It measures 84 m m . and consists of 64 segments. |
