ON DIPLOZOOX NIFPONICUM, N. SP. 



17n 



of this class consists of vessels with :i distiiK-t wall, 2) that these 

 vessels are of two kiln Is, tlie larger oiies serving iii:iiiily f<jr leading 

 out the contained fluid, and the cnpillarÎL's which end in fnnnel-sluiped 

 little bodies shewing the so-called " Wimperflannne " in the interior, 

 and which are the most important part of the system. 



In DipL nipponiciun^ as in Dipl. panidoxum^ two main canals (an 

 always be distinguished on each side of the body, one of which is 

 larger than the other and opens to the exterior by means of a circnhir 

 o])ening on the dorsal side^', close to the lateral mai'gin, a short dis- 

 tance posterior to the pharynx (Fig. 2, eo). Immediately at the 

 entrance of the o])eniiig, the vessel presents an enlargement (the so- 

 called " vSammelrohr "), then proceeds anteriorly to about the level 

 of the pharynx, whei-e it bends backward and proceeds posteriorly, 

 winding more or less on the w^ay, and giving off but a few 

 branches. On reaching the posterior suckers, it bends inward to 

 them and reaches nearly the posterior margin of the body. Here it 

 turns on itself and proceeds anteriorly, following closely its former 

 course, but this time liberally sending ont branches which anastonnjse 

 with one another and with those from the opposite side of the body. 

 Anteriorly this main vessel reaches the upper lip of the mouth, where 

 it divides itself into numerous branches, having also become smaller 

 during its course. These two main vessels follow closely in their 

 course that of the ventral nerves, on whose dorsal side they are situat- 

 ed except where they make windings towards one side or the other. 

 I have sometimes observed a direct connecting vessel between the two 

 main ones. Within these vessels as w^ell as the branches that proceed 

 from them are seen, in a living specimen, active vibratory movements, 

 which generally come to view only after the animal has been left f)r 



1) Cf. Brauu — Uebur (.lie Lage d. Excaetiouspori bui d. ectupar. Trematudeu. Zool. Auz. 

 Jahrg. XII. 1889. p. 620. 



