Australian Earthivorms. 75 



In segment 6 there is an umisually large development of 

 branches from the lateral, one supplying the alimentary canal 

 in this segment, and two running forward to do so in the more 

 anterior ones ; while one large vessel passes to the ventral 

 surface. In segments 6-9 the lateral gives branches to the 

 posterior septum (B.S.) in each segment, and in 7-13 it re- 

 ceives branches from the alimentary canal, derived from the 

 supra-intestinal in 13-8, and proljably in 7 also, though here 

 the latter vessel is small, and the origin of the branch to the 

 alimentary canal indistinct, appearing in one specimen to be 

 from the commissural vessel close to where it arises from the 

 dorsal. 



The ventral vessel runs the whole length of the body, uniting 

 with the dorsal as described, and sending off a good many 

 branches from segment 4 forv.ards. From 14 back it gives 

 marked vessels to the ventral l^ody-wall in the posterior mesen- 

 teries of the segments. 



15. — Cpyptodrilus hulmei, Speiic< r. 



Megascolides hulmei, 8peiicei-. P.R.S. Vict., 1892. 



Plate XVI., Fig. lo. 



Dissection. — Dorsal vessel single, running the whole length 

 of the body. From segment 17 back it gives off a pair of 

 commissural vessels in each segment to join the ventral, supply- 

 ing the alimentary canal on the way. This arrangement is ap- 

 parently continued to the posterior end, but at the very end 

 of the body the mesenteries are so thick that the vessels, which 

 are here small, are hard to make out. From segment 13 for- 

 ward the mesenteries also become extraordinarily thickened, 

 very much obscuring the blood supply, especially that connected 

 with the ventral vessel. From 16 forward the branches from 

 the dorsal become irregular. In segment 16 theie are two 

 on each side, one running to the ventral and only supplying the 

 alimentary canal (Dorso-intestinal, Bourne). In 15 there are 

 also two. but neither of these reaches the ventral, both ending — 

 after supplying the alimentary canal — in the xiih-ii)testi)iaL 

 which ends on the posterior mesentery of this segment. The 

 anterior pair of these vessels forms a small plexus on the roof of 



