64 ALFRED GIBBS BOURNE. 



"intestinal" networks, i.e. with those networks in the walls 

 of the oesophageal glands. 



The other intestino-tegumentary vessels have relations which 

 are precisely similar to one another (figs. 4, 7, 9, 10). The 

 main portion of the vessel in each case lies closely adherent 

 to the body-wall just behind a septum, i.e. in the anterior 

 portion of a segment ; the ventral end of it is connected by 

 several small branches (fig. 7) with the external intestinal 

 capillary network, while from the trunk numerous branches, 

 especially near the dorsal region, pass to the peripheral net- 

 works. The branches of the intestino-tegumentary vessels 

 are thus of two kinds, peripheral branches and intestinal 

 branches. All the intestino-tegumentary vessels place the 

 peripheral and intestinal capillary networks in communication 

 with one another, a relationship discovered by Perrier for the 

 large anterior pair, which led him to give them the name of 

 intestino-tegumentary vessels, and to compare them to portal 

 vessels. The relationship, or existence even, of the posterior 

 intestino-tegumentary vessels does not appear to have been 

 hitherto described. They are connected with one another, 

 the pair of one segment with that of the adjoining segments, 

 and the one of one side with that of the other, in the intestinal 

 wall, and, I believe, also in the body-wall (figs. 7 and 10). 

 The longitudinal connections in the intestinal wall constitute 

 doubtless the infra-intestinal vessel which is figured by Howes 

 in the ' Atlas of Biology ' (Lumbricus) , and is stated by Benham 

 (4, p. 253) to have been observed by Beddard in Acantho- 

 drilus. 



Hearts.^ — There are eight pairs of rhythmically contractile 



1 I use this term for all rhythmically contractile, circularly disposed vessels, 

 thus including, for reasons stated below, certain anterior branches of the 

 dorsal vessel which do not join the ventral vessel. 



These hearts are either — (1) all connected with the dorsal vessel, or (2) 

 some only are so connected, while others are connected with the supra- 

 intestinal vessel only, or (3) some are connected with the dorsal vessel only, 

 and some with both the dorsal and supra-intestinal vessels (in Pontodrilus 

 and Titanus [see Perrier, 10], in Megascolides [see Spencer, 13], in Megas- 

 colex, suggested as a possible arrangement by Beddard and figured in this 



