ON MEGASGOLEX CCERULEUS. 69 



course equally dense throughout^ and it is therefore possible 

 to speak of separate networks segmentally arranged. 



The most anterior (fig. 8) is connected with the two most 

 anterior branches of the dorsal vessel, those of the ventral 

 vessel, and also the most anterior ramifications of the anterior 

 intestino-tegumentary vessels. 



Following these there is a series of similarly arranged net- 

 works throughout the body, the only exceptions being the 

 slight ones about to be mentioned, and these are due to the 

 presence of the hearts. In segments viii to xiii the connec- 

 tions with the ventral vessel are wanting ; in segments vi to ix 

 there are no direct connections with the dorsal vessel, their 

 place being taken by connections with the hearts of those 

 segments, or rather with the vessels which are the distal 

 connections of those hearts. 



In all other segments there are connections with the dorsal 

 vessel by means of dorso-tegumentary vessels ; of the exact 

 origin of these vessels in segments x to xiii I have no note. 

 In all the segments as far back as xiii, and probably in the 

 next four or five segments also, there are connections with 

 anterior intestino-tegumentary vessels; in all the succeeding 

 segments, and perhaps in the above-mentioned four or five 

 segments, there are connections with the intestino-tegumentary 

 vessels of the various segments. 



Intestinal Networks. — All the capillary networks in the 

 walls of the alimentary canal, excepting in its most anterior 

 region, where the capillaries are more superficial and belong to 

 the peripheral networks, fall naturally into one group, and are 

 described below in detail for Megascolex. 



These networks, as I have found them in Megascolex, diifer 

 considerably from those described as occurring in other genera. 

 I select for detailed description one of the segments xliii to 

 cxxxv (fig. 10). 



There are two capillary networks in the alimentary canal 

 wall — an internal deep-lying network and an external more 

 superficial one. 



The internal network (fig. 10), which corresponds to the 



