66 Gwyii n etJt Bachana n : 



5. — Perichaeta obscura, Spencer. P.R.8. Vict., 1892. 

 Dipopochaeta obscura, Spencer. 



Plate XIV., Fig. :•). 



Dissection. — Th<- dorsal vessel is single and swollen in 

 segments 13-17, running the whole length of the body, and 

 breaking up in segment 1, but connected with the ventral by 

 a commissural Yessel on each side at the posterior end of the 

 body. It gives off from the posterior part of segment 12 a 

 supra-iutesfi/ial, and from this point also a heart arises on each 

 side. The supra-intestinal gives off a pair of hearts in segments 

 10 and 11, in the posterior part of the segment, and also, in 9, 

 10, 11 and 12, a vessel to the alimentary canal, raid joins the 

 dorsal at the front of segnient 0. From 9-4 the dorsal gives 

 oft* posteriorly in each segment a pair of commissurals, but in 

 3 this vessel does not seem to pass to the ventral surface, and^ 

 in 4 it gives off on each side a lateral which runs back and 

 forms the sub-intestinal ending on the posterior septum of 13, 

 and receiving in segments 9, 10, 11 and 12 branches from the 

 alimentary canal derived from the supra-intestinal. 



The ventral vessel is single along its Avhole length, and breaks 

 up in segment 1. 



6. — Perichaeta manni, Spencer. P.R.S. Vict., 1900. 

 Diporochaeta manni, Spencer. 



Plate XI\\, Fig. 6. 

 Dissection. — Dorsal vessel single, breaking up in segment 1 

 and swollen in 13-17. Connected with the ventral by a commis- 

 sural vessel on each side in 13, and giving off in this segment 

 a supra-intestinal, running forward to the front of ;!<. In seg- 

 ments 10, 11 and 12 this gives rise to a pair of hearts pos- 

 teriorly in each segment, and also n branch to the alimentary 

 canal. From 9-5 the dorsal gives oft' commissurals in the hinder 

 part of each segment, that in 6 sends a liranch forward to 5 and 

 back to 9, as the lateral to be continued in segments 10, 11 and 

 12, as the suh-intes final. If vessels come off from the dorsal in 

 front of 4 they are too small to trace round. The ventral is 

 single, and runs forward to break up in segment 1. 



