JAPANESE LAND LEECHES. 995 



Vascular system. With regard to the vascular system, Orohdella 

 seems to occupy an intermediate position between Hiriido and Herpo- 

 hddla (syn. Nephelis). There are four main trunks of ]:)lo(>d vessels, 

 that correspond to the dorsal, lateral, and ventral vessels of Hirudo 

 respectively, but the blood spaces that are found anastomosing between 

 various organs are com|)aratively very wide and ])reseiit characters 

 similar to those of Herpohdella. The wall of the hiteral vessels is 

 furnished with muscles, which makes it most ])rol)al)le that these 

 vessels pulsate in the living state. The dorsal trnnk is not so con- 

 spicuous as the lateral ones, having no muscular layer in its wall. 



In every somite of the median portion of the I)ody, there is one 

 pair of large irregularly spherical blood-spaces, in which the funnels of 

 the nephridia open. In Herpohdella there are two pairs, l)ut in Orohdella 

 I could find but one pair. The position of these spherical sinuses is 

 nearly the same in the two genera.; in Orolnlella they seem to be a 

 little nearer the ventral surface of the body than in Herpohdella. The 

 blood-s])aces receive their blood from the lateral vessels by means of 

 very short transverse vessels, of which one pair is found in each 

 somite. 



Nephridia. The funnel that opens into the blood -space consists 

 of five or six cells, forming so many spoon-shaped lobes arranged 

 radially. Upon this funnel follows a capsule filled with small cells, 

 analogous to that of Glossosiphouia (syn. Clepsine) (181)4) but not so well 

 developed. The funnel is thickly ciliated over the whole surface, and 

 the lumen opens freely into the interior of the capsule. How this latter 

 organ communicates with the remaining sections of the nephridium 

 I am at present unable to tell, but it is probable that the intracellular 

 canal of the nephridial string stands in connection with the lumen 

 of the capsule. The beginning of the nephridial string certainly lies 

 directly in contact with the wall of the capsule. The winding of the 



