Japanese Freshwater Triclads. 3 



a^. Eyes situated a considerable distance apart from head 

 margin. 



Eyes distributed in two longitudinal tracts; tentacles 

 moderately long, obtusely pointed at tip; body colourless 



or presenting various sorts of hues 



7. Sorocells Sapporo Ij. et Kab. 



b^. Eyes distributed close to head margin. 

 «^ Eyes in irregular rows. 



Tentacles long, more or less rounded at tip; body 



generally of a sepia brown colour 



(S. Polycelis anHculata Ij. et K a v,. 



Tr. Eyes in a single row. 



a^. Tentacles moderately short, pointed at tip; body of a 



dark olive-like brown colour ...9. Ploycelis ijimai Kab. 



//^ Tentacles longer, more pointed at tip; body of a dark 



brown colour, showing two longitud^inal ill-defined 



darker l)ands 10. Foh/celis karafto Ij. et Kab. 



BdellocephalH annamlfilei Ij. et Kab. 

 (PI. I., fig-. 1.— Text figs. 1,2.) 



A few specimens of this species were collected by Dr. N. 

 Annandale and Mr. T. Kawamura in October, 1915, in Lake Biwa, 

 on a muddy bottom at a depth of 30-45 fathoms. 



Form and Dimension. — The body, which is of large size and 

 of a very firm texture, is elongate-oval with the narrow head lobe 

 distinctly marked off from the trunk. When in motion, the 

 breadth of the head lobe is less than one-third that of the broadest 

 part of the trunk. The frontal margin of the head is crenate and 

 strongly arched in the middle parts, spreading on each side into 

 lateral lobes which are not prominent. When viewed from the ven- 

 tral side, the head lobe exhibits some small adhesive folds on the 

 inferiorly turned swollen edge, as is shown in text fig. 1; close be- 

 hind that edge there exists a groove-like depression. The trunk, 

 being rounded at the posterior end, is of considerable thickness, 

 rather strongly convex dorsally, but tiattening ventrally. Large 



