NOTES ON TWO NEW SfEClES OF JAPANESE POLYCLADS. 



595 



may be designated the vagina bulbosa. It opens to the exterior by 

 the small female aperture situated close behind the male aperture. 



Remarks. — This interesting new genus and species agrees with the 

 Diplosolenid genus Pseudostylochus, recently instituted by us 1 , in the 

 general plan of genital end-organs. Nevertheless, it stands widely at 

 variance from that genus in the presence of marginal eye-spots, not to 

 speak of other minor points of difference. Taken all in all, it seems, 

 in our opinion, to be more nearly allied to Stylochus than to any 

 other known genus, notwithstanding the peculiarities it presents in 

 organization. Hence we are inclined to place it in the Stylochidse 

 If we are right in this, the diagnosis of that family, last given by 

 BOCK 2 , should be emended to run somewhat as follows : 



Fam. Stylochidœ. Craspedommata of oval body-shape, with or 

 without tentacles. Tentacular and cerebral eyes in distinct clusters 

 marginal eyes in a crowded row or rows running around body. Pharyn- 

 geal chamber much folded in relation to plicated pharynx. Prostatic 

 gland a free sac- like organ opening into ejaculatory duct. With either 

 true or accessory seminal vesicle. Penis conical or tubular. With or 

 without vagina bulbosa ; accessory vesicle to vagina paired, single, or 

 none. 



The following are the chief features which distinguish the new 

 genus Neostylochus : 



Stylochidae with oval body. Tentacles absent. Marginal eyes 

 confined to frontal margin. With true seminal vesicle. Prostatic 

 gland situated dorsal to seminal vesicle. Penis of a slenderly tubular 

 shape. Accessory vesicle of vagina single, large. 



Now, the following seven genera have hitherto stood in the 



1) Yeri and Kaburaki. 1918. Bestimmungsschlüssel für die japanischen Polycladen 

 Annot. Zool. Jap. VoL IX. Part 4. — Description of some Japanese Polyclad Turbellaria. 

 Journal of the College of Science, Imp. Univ., Tokyo. Vol. XXXIX. 



2) Bock, Sixtex. 1913. Studien über Polycladen. Zoologiska Bidrag fràu Upsala. 

 Bd. 2. 



