12 ON A REMARKABLE SYLLIS-BUD. 



hairs at the inner border (fig. 2a) ; the length of this ter- 

 minal piece is not the same in all bristles , being in some 

 of them one third longer as in others. Besides, the seti- 

 gerous region of the foot possesses a dorsal tuft of long, 

 translucent, paddle-shaped epitocous bristles; the tip of 

 these ordinarily is bend and sometimes has a fimbriated 

 appearance (fig. 2b). 



The condition of the anal region is open to doubt; in 

 one specimen I observed an anal segment without feet or 

 terminal cirri , but with wing-shaped processes along its 

 lateral sides (fig. 3). 



In the base of each foot, except in that of the first 

 segment, a large dark-brown coloured sac is situated, 

 which appears to be capable of being extruded through a 

 small opening at the ventral surface ; at least in some 

 segments this sac was nearly totally everted , whereas in 

 others I found only a part of it turned outward (fig. 4). The 

 largest extruded pouch measures about 0.24 m.m. in length. 

 Not doubting that these bodies represented the segmental 

 organs, I tried to find out the internal openings of them. 

 In consecpence of the transparency of the body I succeeded 

 to recognize the internal mouth of the first segmental organ , 

 situated in the second segment (fig. 5). This mouth has 

 the shape of a rather large, shallow funnel, correspon- 

 ding by a short, broad duct with the body of the pouch. 

 The wall of this duct appeared to be composed of cells 

 and its external surface shows a thin layer of pigment; 

 in the posterior region of the body the segmental duct 

 was therefore recognizable as a thin brown stripe. In 

 transverse sections (fig. 6) each segmental pouch appeared 

 to have a somewhat renal shape, being provided with a 

 notch at its base ; this basal region usually is not pigmen- 

 ted, the remaining portion of the sac beiug covered with 

 a thick layer of dark-brown pigment, which seemed to be 

 enclosed in an external layer of polygonal cells. The in- 

 ternal surface (fig. 7) of the pouch is covered with a layer 

 of high, cylindrical cells with a granular protoplasma and 



Notes from the Leyden Museum, "Vol. XI. 



