NEW SPECIES OF OCNERODRILUS. 24I 



necessary blood. In the anterior somites these trunks 

 branch repeatedly, forming in somite i and in the anterior 

 part of somite ii a perfect network of capillary blood- 

 vessels, which connect with the capillaries from the dorsal 

 and ventral vessels, both above and below the pharynx 

 and oesophagus. The vessel supplying the oesophageal 

 diverticulum branches in the organ into numerous parallel 

 vessels, which again collect into one trunk, as has been 

 already mentioned. There are no dark epithelial pig- 

 ment cells on any of the vessels, but the muscular part 

 of the dorsal vessel and of the hearts is thick. 



The ventral main longitudinal vessel emits one second- 

 ary vessel in each somite (fig. 30, /. v. v.). This vessel 

 starts out anteriorly to the dorsal secondary vessel (fig. 

 30, /. d. v.), and is parallel to the latter. It branches as 

 soon as it reaches the body-wall into two distinct trunks, 

 one smaller descending, and one larger ascending. The 

 former one is very short, and extends, with branches, 

 below the neural-ganglion, but does not anastomose with 

 the vessels from the dorsal branch. The ascending 

 branch again divides in two parallel branches, which 

 closely follow the parietes and again branch, forming a 

 wide meshed capillary network on the dorsal side of the 

 body-wall. This secondary ventral vessel is present in 

 all the somites, even in ix, x and xi. The secondary 

 branches of the dorsal and vental vessels are of about 

 equal length and thickness, but the branch from the 

 ventral vessel is much more branched than the dorsal 

 secondary vessel, which is almost entire, and even in the 

 ventral region emits few branches. A similar arrange- 

 ment is found in Sparganophilus, lately described by 

 Benham. (Quart. Journal Micr, Sc, Nov., 1892.) 



These secondary vessels are similar in the various 

 species, except in Ocnerodriliis limicola and Hendriei, in 



