Description of Some Japanese Polyclad Turbellaria. 2 1 



genital apertures between mouth and posterior body end. Without 

 true seminal vesicle. Prostate separated from ejaculatory duct and 

 opening into it by a distinct duct, Penis unarmed. There occur 

 a duplicate penial system either in front of or behind the functional. 

 A part of vagina forming a prominent compact spiral coil. Vagina 

 and vaginal duct running nearly in a circle and both opening into 

 antrum femininum just within the external female aperture. 



B. Sectiou SCIHEMATOM»ATA Bock. 



Family Lepteplanidœ Stimfson (Bock 1913 emend.). 



Genus Notoirtana Laidlaw 1903. 



5. Notoplana htimilis (Stimpson). 



(PI. II., fig. G.—Textfigs. 9, 10). 



Leptoplana humilis, Stimfson 1857, pp. 4, 9. — Diesing 18G2, p. 583.— Lang 

 1884, p. 496. 



The specimens, which we identify with Leptophna humilis 



described by Stimpson from Hokkaido, is one of the commonest 

 species in the neighbourhood of Misaki. Numerous specimens of 

 the species have also been captured near the low-water mark at 

 Shirahama in Prov. Awa and at Otaru in Hokkaido. 



Body delicate, of an elongate shape in the creeping state, 

 rounded at the anterior end, uniformly broad in most parts, 

 gradually tapering to a blunt point at the hind end. Dimensions 

 usually about 15 mm. long by 5 mm. broad, though largest in- 

 dividuals may reach 25 mm. in length. 



Translucent; in dorsal view of an olive-buffy colour growing 

 deeper towards median parts, partly due to the guts externally 

 discernible with more or less distinctness ; generally a light coloured 

 longitudinal stripe present over the slightly folded pharynx. 

 Testicular follicles and ovaries may appear as whitish spots. 

 Ventral surface much paler than the dorsal. Genital end-organs 

 also visible with moderate distinctness. 



Tentacles small and somewhat rudimentary, bluntly pointed. 



