80 GivynnetJi Buchanan : 



3. That as far as can be made out from dissections there 

 seems to be a correhition between the anterior ending of the 

 supra-intestinal vessel and the origin of the hearts — when the 

 former opens into the dorsal vessel at the anterior end the 

 hearts having no connection with the dorsal ; but if the supra- 

 iniestinal merely breaks up, the hearts take origin from both 

 it and the dorsal, except in the case of D. daralUa and (\ 

 gi%ipsJ an (liens, in which the anterior junction of the supra- 

 intestinal and dorsal is very fine, if present. This worm, how- 

 ever, is aberrant in other particulars, e.g., the double dorsal 

 vessel, so it may not be possible to place it under any 

 generalised heading. 



i. That the function of the hearts is mainly propelling, 

 though they may give off branches, supplying organs in their 

 course — e.g., nephridia ; and the place of the ordinary one or 

 more commissural vessels, passing from the dorsal to the 

 ventral behind the hearts, and supplying the alimentary canal 

 on tlie way, is in their region, taken by the branch from the 

 supra-intestinal, which is in some cases very large. 



5. That the supra-intestinal varies in the position of its 

 origin, but is apparently ahvays connected with the dorsal at 

 ^r close to its hinder end. 



6. That the lateral is a constant feature, tliou^h varying in 

 its point of origin — seeming, however, most frequently to ariye 

 from the commissural vessel in segments 4 or 5. That it is 

 not always observed to divide into a forward and a backAvard 

 running portion may be due to the small size of the former, 

 though in many it was most marked. Bourne (11), in a note 

 on p. 62, says. '' These vessels (Intestino-tegumentary), or at 

 Hny rate, some h.iving similar relations, have been stated to 

 communicate directly with the dorsal vessel in Limbricus." 

 In M. coeruleus, however, the only direct connection of the in- 

 testino-tegumentary with the dorsal, which he describes, is in 

 the capillary network at the anterior end. The lateral usually 

 runs on as a separate sub-intestinal on each side, but occasion- 

 ally the two become united ; while in some cases, as in P. 

 dorsal in and 1\ ten ax, at the anterior end it seems to take an 

 important function in relation to the supply of the ventral 

 body-wall, and presumably of the nephridia. Howes (12) 



