A iistralain Edrtlncorins. 213 



of the hearts, as has been said, though it becomes rather indis- 

 tinct between them, and is connected with the hirge sinus 

 around tlie alimentary canal in this region, though not by ver)^ 

 definite vessels, passing to the sub-intestinal. 



The ventral is single, and passes forward to where it breaks 

 up into fine branches, w^hich may or may not join the dorsal. 

 In '2 it sends branches to the alimentary canal, and behind the 

 heart region a vessel to the posterior septum and ventral body 

 wall in each segment. As has been said, the connection between 

 the dorsal and ventral by w^ay of the alimentary canal is indis- 

 tinct. Thi<. however, is common, as l^eddard (p. 72) remarks 

 that in earthworms the conuiiissurals are confined to the 

 anterior segments of the body, but in the embryo of Lumbricus 

 eai-h segment has a pair of commissurals. Evidently, therefore, 

 it is better to call these vessels in the hinder regions of the 

 bodv dorso-intestinal. 



3. — Notoscolex queenslandica,^ Spencer. 



Cryptodrilus queenslandica, Spencer. Proc. Roy. 

 Soc. \'ict., vol. xiii., pt. i., 1900. 



Plate XL., Fig. 3. 



Dis'^ectio//. — Dorsal vessel single, swollen in segments 18-10. 

 and giving oti' distinct dorso-tegumentary vessels to the hinder 

 mesenteries in those posterior to the hearts. The tegumentary 

 blood system is very well marked along the whole length of the 

 body. The alimentary canal in the intestinal region is Avell 

 supplied by large vessels arising from the dorsal which ap- 

 parently end blindly : but in the segments immediately behind 

 tlif^ hearts, which have vascular swellings in 16 and calciferous 

 glands in 14 and 15 (Spencer, loc. cit.), these vessels end in a 

 blood sinus below the alimentary canal. The commissurals, if 

 ])resent, are very indistinct along the intestinal region. Tlie 

 dorsal runs forAvard to the first segment, when it breaks up 

 into very fine branches after giving off a small vessel connect- 

 ing with the lateral. From 9-2 the dorsal gives rise to a pair 



1 Michaelseii, loc. cit., p. 162. 



