THE OEPHYREA OF JAPAN. 33 



color. Skill- bodies small and flat, contaiiining a few hook-like 

 structures (?) with the points directed outwards. At introvert- 

 basis and near the posterior end of body, the skin-bodies though 

 but slightly elevated above the surfece are so large (0.38-0.4 mm. 

 in diameter) as to be easily recognized with the naked eye. 



Longitudinal muscles average 20 in number ; they are broad 

 and anastomose but rarely. Circular muscles are likewise divided 

 into distinct but narrower bundles. Four retractor muscles arise 

 a short distance behind the anus, the ventral pair between the 

 7th and the 8th longitudinal muscle. Rectal diverticulum present. 

 Spindle-muscle fixed to the body-wall at both its ends, anteriorly 

 giving off two lateral branches. The single fixing muscle has 

 two roots. Dorsal vessel with numerous but short contractile 

 villi. Segmental organs short, connected with the body-wall for 

 the anterior one-fourth of their length by a mesentery ; their 

 external apertures lie between the 3rd and 4th longitudinal muscle. 

 A large number of crescent-shaped dissepiments are present on 

 the inside of body-wall in the region between the anus and the 

 posterior body-end. 



This cosmopolitan species is very widely distributed in Japan. 

 Numerous specimens have been obtained from various localities ; 

 as for instance, Kamo (Province of Eikuzen) ; coasts of the Tokyo 

 and Sagami Bays and of the Inland sea ; Kagoshima (Kiushiu) ; 

 Koniya in Amami-( )shiina ; Naha and Itoman (Kiukiu). The 

 specimens from various localities in Japan proper, including 

 those from Kagoshima, are 20-30 (?;>?. in total length and 8-12 

 mm. in breadth, the introvert and the body proper being nearly 

 uniformly broad. The color is yellowish brown in the male and 

 reddish brown in the female. On the other hand, the specimens 



