110 U. TAKAKUKA. 



lateral vessels (I. v.) are generally recognized everywhere, by their 

 greater sizes and paucity in branches except in the oesophageal 

 region. They are situated on the ventro-lateral sides of the digestive 

 canal, except in the head, where they gradually shift their positions 

 dorsad and finally take the lateral position. In the oesophageal 

 region, various anastomosing branches are separated off towards 

 the outer and inner sides and spread in the flat lateral edges of 

 the body. It is through these canals that they are indirectly con- 

 nected with the dorsal vessel. At the tip of the snout, the numerous 

 branches also form networks, which are posteriorly continued to those 

 in the lateral edges. Some branches from the vessels form a canal 

 system which occupies the ventral side of the body. In fig. 3, 

 this ventral canal system is shaded. Sometimes ventral con- 

 nections under the oesophagus join the canals of the opposite 

 sides {v. c), a fact hitherto not noted in Metanemertini. The system 

 is connected in several points to that (not shaded in the figure] 

 situated on the dorsal side. In the middle region, the lateral vessels 

 have only a few branches (fig. 4, /. v.). Unlike those of M. grossa, 

 they have no branch at the posterior region, and hi the acetabulum no 

 trace of a complicated vascular system, as described by v. Kennel, is 

 found. 



Of the excretory system no essential difference can be detected in 

 the present species, except that, the external opening is not situated 

 ventrally, but dorsally to the lateral nerve stem and opens at the 

 dorso-lateral side of the body. 



The peculiar feature of the nervous system is the position of the 

 posterior commissure of the lateral nerve-stems. There is no trace of 

 the anal commissure above the anus, but posterior to it, along the 

 posterior margin of the acetabulum, a strong commissure is distinctly 

 observed as shown in figs. 1 & Cr (a. c). At the points, from which the 

 lateral nerve-stems enter the acetabulum, they slightly become larger, 

 as v. Kennet, observed, and between these points a slender commis- 

 sure runs along the anterior side of the acetabulum (ac. c). This 



