EKKANTIAÏE POLYCHAETA OF JAPAN. 77 



Aphrotida watasei n. sp. 



PL I, fig. 5 ; PL IX, fig. 16. 



Of tho two oxamplos procurod by Prof. S. Wataöe, at Nameri- 

 kawa, tlio larger, consisting of 38 parapodiatocl segments, mea- 

 sures 70 nnn. in length, and 36 mm. in maximum breadth including 

 parapodia ; and the smaller 55 mm. in length, 28 mm. in breadth, 

 with 34 segments. Dorso-ventral thickness 15 mm. and 13 mm. 

 respectively. 



Dorsal surface of l3ody entirely covered by a thick, dusky 

 brown felt, loaded with mud and sand particles. 



Prostomium roundish, the length almost equal to the breadth ; 

 the maximum width lies nearer to the anterior than to the posterior 

 margin. A transverse ridge is found along the antero-dorsal margin 

 of prostomium, and from the mid anterior portion of this ridge 

 arises a median tentacle, wliicli consists of a long, slender style 

 and a ceratophore of about ^ tlie length of the style. Frontal 

 tubercle short and laterally compressed, as usual, and placed 

 between the paired subtentacles, which are comparatively large 

 reaching about 5 times the length of the inedian tentacle. Eyes 

 invisible. 



Dorsal setae (or spines) brownisli black in colour, having 

 metalic iri(les(.'ence, are almost hidden a]uong tlie felt, and a series 

 of iMiiidles of (he lateral liaii's are loaded with mud, so as to 

 apjieai' like tlie iViiiges uii the sides of the body. \'entrai setae 

 may be dixided into three gr()U[)s the setae in the superior group 

 ainoiiiil to I ; those iu tli<' middle [<..) 7 ; and those in the inferior 

 to 11. riirorhniatel}- ahimsl all tlic tips of setae were broken, but 

 ill dial wliicli was not injured has a curved tips as shown in 

 PL IX, fig. 16. 



