218 GxvynnetJi Buchanan: 



branches to the alimentary canal above which it ends blindly 

 in 6. 



The ventral vessel runs forAvards and breaks up at the anterior 

 end. sending a branch to join the dorsal as described, and be- 

 hind the region of the hearts it gives a very definite pair of 

 vessels in each segment and the ventral body wall running along 

 the septum. 



6.— Cpyptodrilus saccarius, Fletcher. Proc. Linn. Soc. 



N.8.W., 1887. 



Plate XLT., Fig. 6, and Plate XLTI., Fig. 8. 



Dorsal vessel single, slightly swollen in segments, 14-10. It 

 passes forwards to first segment, becoming very indefinite in 

 the anterior two or three, but apparently joining the ventral in 

 1. From 14 backwards it gives off a commissural vessel on each 

 side, which supplies the alimentary canal, but in all cases in this 

 form the connections with the ventral vessel are fine. There 

 are four pairs of hearts, the last arising in the posterior part of 

 segment 13, from a double origin — by a fine branch from the 

 dorsal and a much more definite one from the supra- intestinal. 

 Tliis latter makes its appearance in segment 13, and is very 

 marked, giving large branches to the calciferous glands, which 

 are conspicuous structures, in segments 13-9. It apparently be- 

 comes discontinuous in segment 12, but on examining micro- 

 scopically, is found to be represented l)y an exceedingly fine 

 vessel between the hearts in 11 and 12. It ends blindly above 

 the alimentary canal in segment 8. 



From segment 9 forwards the dorsal gives oft' a pair of com- 

 missural vessels at the posterior part of each segment, that in 9 

 being very well marked. From 9-6 the commissurals give 

 branches to the posterior septum of the segment, that in 6 

 being small. Those commissurals in 2, 3 and 4 are very in- 

 distinct, but apparently join the ventral vessel, while that in 5, 

 after giving a branch to the alimentary canal, joins a marked 

 lateral, which in its turn sends a branch to the ventral vessel. 

 It also joins its fellow of the opposite side under the alimentary 

 canal in segment 5, and sends a branch forward to the alimentary 



