Australian EayrtUivorius. 77 



ance niav have been due to the vessels being covered by the 

 muscles. In the hinder part of 13 the dorsal gives off a supra- 

 intestinal, running forward to end in 8. This gives rise in the 

 posterior part of segments 10, 11 and 12 to a pair of hearts, 

 each receiving, as in many others, a small branch from the 

 dorsal. In the same position in segments 9-4 the dorsal gives 

 off a pair of conunissural vessels in each segment, running 

 round to the ventral, and giving branches to the alimentary 

 canal (B.A.) and ventral body-wall (Br.W.) on the way in seg- 

 ments 9-6, and in 5 sending back a /rt^e/r//. which is continued as 

 a sub-intestinal on each side in 9, 10. 11 and 12. and which in 

 these segments receives branches from the alimentary canal, 

 derived from the supra-intestinal, and perhaps also in segment 

 8. 



The ventral is connected with the dorsal as before described, 

 and behind the hearts gives clear branches to the ventral body 

 M all. beinof sin^rle along: the whole length of the body. 



17. — Dipopochaeta tanjilensis, Spencer. 



Pepichaeta tanjilensis, Spencer. P. U.S. Vict., 1892. 



Plate XVL, Fig. 17. 



Dissection. — Dorsal vessel single, swollen in segments 13-16, 

 and joining the ventral by a single commissural branch on each 

 side at the posterior end of the body. This arrangement con- 

 tinues in each segment till 13, in which the dorsal gives off as 

 well a suijra-intestinal, swollen in segments 10-12, and run- 

 ning forw^ard to the front of 8. The dorsal runs forward to 

 the first segment, possibly passing to the ventral surface, but 

 is here very small, and gives off a pair of commissural vessels 

 on each side in the posterior parts of segments 9-5, those in 

 9-6 giving branches to the ventral body wall (Br.W.), that in 

 y giving a branch running back as the lateral on each side, and 

 receiving vessels from the alimentary canal, derived from the 

 supra-intestinal in segments 8-12. A pair of J-ea-fs arise at the 

 back of the segment from the supra-intestinal in 10, 11 and 

 12, and run round to the ventral vessel, each receiving a very 

 small branch from the dorsal at their point of origin. 



