Terrestrial Planarians from Japanese Territories. 



35 



breadth, while one of the smallest measured only 13 mm. long by 

 1-5 mm. broad. 



The dorsal surface is of a uniform velvety black, except on 

 the head, which reveals a dark rusty brownish tone. Ventrally, 

 the colour is somewhat paler than that of the dorsal side, except 

 for the surface of the sole which is, as usual, of a plae gray colour 

 and anteriorly presents nearly the form of an arrow-head by reason 

 of the shade of colour. On either side there exists a longitudinal 

 zone much paler than the rest of the ventral surface. 



Numerous eye-spots are densely set, 

 surrounding the entire fringe of the head 

 lobe, and are continued round to the sides 

 of the neck, where they are more ventral 

 than dorsal and form a closely crowded 

 cluster. Further, the eye-spots are ar- 

 ranged in sparse numbers almost through- 

 out the whole length of the body, on the 

 ventral side along and just within the 

 margin of the body. 



The mouth-opening which leads into 

 the peripharyngeal chamber is placed 

 «lightly behind the centre of the body in the mid-ventral line. 



The common genital aperture is situated at the hind end of the 

 anterior third between the mouth-opening and the posterior end 

 -of the body. 



The epidermis made up of columnar cells is much higher on 

 the dorsal surface than on the ventral and provided with cilia on 

 the surface of the sole only. Situated between the epidermic cells, 

 except those that are on the sole-surface, are found minute and 

 slender rhabdites, which originate from their mother-cells, scattered 

 in fair abundance in the parenchyme farther inwards to the 

 epidermis. Deeply embedded in the parenchyme along the median 

 zone of the body are enormous quantities of slime glands which 

 open out on the sole-surface. 



Immediately beneath the basement membrane comes the 

 superficial muscular system composed of two layers of outer circular 



Text fig-. 17. Distribution 

 of eye-spots in Placocephalus 

 fuscatus (Stimpson). 



