Description of Some .Japanese Polyelad Turbellari 



31 



SI 



Textfig. 34. Genital end-organs of P. obscurus 

 section. Semi diagrammatic. 

 Index letters as in textfigs. 4, 7 au d 10. 



in sagittal 



•duct which pursues a short sinuous course before entering the 

 seminal vesicle (sv) at the anterior end. The vesicle gives lise to 

 the ejaculatory duct (ed), which, after receiving at base of penis (p) 



the duct of the mus- 

 cular elongate-ovoid 

 prostate (pr), pro- 

 ceeds backward to 

 open at the tip of 

 penis. The small 

 conical penis is near- 

 ly horizontally dis- 

 posed in the antrum 

 musculinum. 



The comparatively small pear-shaped accessory vesicle (av) 

 gives rise anteriorly to the median egg-canal (ec). After receiving 

 the unpaired uterine duct (uu), the egg-canal extends a short dis- 

 tance further foreward, surrounded by numerous shell glands 

 (5*7); it then bends abruptly ventrad and backward to expand into 

 the vagina (i?). The unpaired uterine duct divides into two uteri, 

 which run anteriorly along the margin of pharyngeal sheath on 

 either side and join together in the median line in front of the 

 pharynx. 



As will be seen from the above description, the present species 

 resembles Pseudostylochus fulvus previously described, but may be 

 distinguished from this by the difference in colour and size of body 

 as well as in certain characteristic points of genital organs. 



Genus Callioplana Stimpson 1857 (emend.). 



This genus, represented by the single species C. marginata 

 described from " Ousima " by Stimpson, has since been considered 

 by authors to be identical with either Stylochus or Planocera. 

 From our own study of what may be regarded to be the Stimpson s 

 genus and species, we are inclined to keep up the genus. It may 

 safely be stated that it should be ranged under the Diplosolenidœ. 

 although it shows some points of resemblance to Woodworthia of 

 the Stylochidœ. 



