34 Art. 9.— M. Yeri and T. Kaburaki : 



shell glands (sg). The passage runs immediately dorsal to the 

 penis sheath, to open to the exterior close behind the male 

 aparture. 



Suborder COTYLEA Lang. 



Family PsemloceridiB Lang. 



Genus Thyaanoxoon Grube 1840. 



16. Thysanozoon f.rocchii (Geube). 



(PI. I, fig. 11). 



Thysanozoon brocchii, Lang 1884, pp. 525-536. 



The species of Thysanozoon found fairly commonly in the neigh- 

 bouring coasts of Misaki and Matsuwa, we are inclind to hold to 

 be specifically inseparable from T/i. brocchii of the Mediterranean. 



Body broadly oval, leaf-like, with somewhat frilled margin. 

 Characteristic is the presence of numerous small, slenderly conical 

 papillae all over the dorsal surface. Generally speaking, they are 

 best developed in the middie parts, and grow smaller and more 

 apart from one another towards the body margin. Large speci- 

 mens with completely developed genital end-organs reach 35 mm. 

 in length and 2.1 mm. in breadth. 



Colour of dorsal surface purplish gray or yellowish purple, 

 with a whitish or yellowish median stripe running posteriorly 

 from behind cerebral eyes. The dorsal papillae are generally of a 

 dark grayish colour with a tint of purple, except at the base which 

 is colourless. Frequently they exhibit a few number of. white 

 dots near the tip. In some of the specimens, which came under 

 our observation, the papillae were in part of a whitish or yellowish 

 colour in the median longitudinal or in the middle transverse zone 

 of the body. Ventral surface much lighter-coloured than the 

 dorsal, somewhat darkish along the margin, but nowhere with 

 pigments. 



Marginal tentacles appear as fleshy outgrowths of the anterior 

 margin of bod} 7 . 



Numerous eye-spots distributed on the tentacles; cerebral 



