ON MONOPYLEPHOEUS LIMOSUS. 3 



sigmoid, furcate ; branches small and nearly straight. Each seta- 

 bundle consists mostly of 3-5 setae, fewer posteriorly. Pharynx 

 in segments II and III ; pharyngeal glands well developed and form- 

 ing four longitudinal rows in segment III. (Esophagus in segment 

 IV. Intestine commences in segment V, and chloragogues mostly 

 in segment VI, but sometimes in segment V. Cœlomic corpuscles 

 very abundant behind segment IV. Supra- and subintestinal vessels 

 are wanting. Integumentary networks well developed. No direct 

 communications between the dorsal and ventral vessels. Five pairs 

 of dorsal integumentary vessels in segments VI-X, much dilated 

 (cll^g). A longitudinal heart, a part of the dorsal vessel, lies in 

 segments JV-JXI. Unicellular valves present in the dorsal and 

 dorsal integumentary vessels behind segment III. Anterior nephridia 

 in segments VII-IX (an 1 _ 3 ), posterior ones beginning in segment 

 XII (pn x ) ; both of the same form. Nephridiopores at about 

 anterior one -fifth of a segment on the ventral setal lines. Testes in 

 segment X (te). Ovaries in segment XI (ov). Anterior sperm- sac 

 in segment IX (a.s). Posterior sperm-sac in segments XI-?XVI 

 (p.s). Ovisac in segments XII-?XVIII. Prostate diffuse. Sperm- 

 ducts short, opening into a wide median spermiducal chamber 

 (sp.d). A male pore at about the anterior two-thirds of the 

 ventral median line of segment XL Saccular portion of sper- 

 mathecae paired; their common opening at about the anterior one- 

 fifth of the ventral median line of segment X ; spermatophores are 

 not present. Body length 50-70 mm. Number of segments 93- 

 130. Hab. — Tokyo ; Okinawa. 



2. Anatomy and Histology. 



Materials were narcotised with beer and fixed with acetic 

 sublimate. 



