Japanese Tricladida Maricola. r^ 



into the moderately wide vesicula seminalis; tlie latter is narrowed 

 inferiorly into the ejaculatory duct terminating at tlie tip of tlie 

 penis, which is of a conical shape and is subvertically disposed. 

 The paired ovary is placed ventrally between the fourth and fifth 

 pairs of the lateral branches of the anterior gut trunk. The 

 oviducts of both sides open separately into the vaginal canal. The 

 receptaculum seminis holds a position posterior to the penis, giv- 

 ing rise at its antero-superior part to the vaginal canal, which 

 runs down to open into the genital atrium from behind. 



Remark. — The present species seems to be most nearly allied 

 in the external features to Pr. (/raciliceps from Hongkong and 

 Fr. trilobata from Avatscha in Kamtschatka, which were <lescrib- 

 ed in 1857 Ijy Sïimpson (56) under the name of Fovla. To me it 

 appears, judging from the description, that the worm in question 

 stands somewhat at variance from both the species in a few" res- 

 pects. The head is in Pr. grac'diceps of a triangular shape, much 

 the same as in the present species, but is wholly devoid of any 

 trace of pigments. In Pr. trilobata the liead seems to present a 

 similar appearance in shape, but a black transverse line exists at a 

 point behind the eyes, unlike in St. trigonoccphala. 



fji'foitlatia liinttli (Ij. et Kab.) 

 (PI. I., figs. 3, 6-8.— Text figs. 3, G.) 



Numerous specimens of this sj^ecies were collected in lb8'J 

 by Professor Kisiitxouye at Ajino, Prov. Bizen, and in P.) 16 by 

 myself at Yobimatsu in the vicinity of the same place. The 

 worms occur in abundance on Llmulus longlspina, attached mostly 

 on the hard surface of the proximal segments of the cephalotho- 

 racic appendages as well as on the gill-books. 



Form. — The body in the creeping state is elongate-slender, 

 nearly uniformly broad almost throughout its length, and is nar- 

 rowed at both its bluntly pointed ends. The tentacles are altu- 

 gether absent. 



/Size. — The large specimens measure 4-6 mm. in length by 

 O'7-l mm. in the broadest part when fully extended. 



