ON THE GENUS NOTOPYGOS. 247 
much projecting on each side, especially in the posterior 
segments and giving to the animal a spiny appearance, 
No eyes are visible. The anterior part of the head shows 
a dark pigment on its dorsal side, except on a small spot 
in the middle and a crescent-shaped one on each side, that 
remain uncoloured. Caruncle wedgeshaped, with five indis- 
tinct, transverse grooves, of a rather loose structure and 
extending to the 4th segment; the median antenna short. 
The mouth seems to be limited posteriorly by the third 
segment, that is folded longitudinally in the middle; the 
surface of the palps is covered with small black dots, like 
in Bathychloeia. The branchial cirri are much longer than 
the filaments of the gills and extend to the middle of the 
dorsum. Ventral setae with 2 to 4 conspicuous denticula- 
tions, dorsal ones smooth or only with a couple of faint 
denticles. The anal orifice probably terminal. The anal cirri 
mushroom-shaped, with a short stalk and a round distal 
part with faintly folded border. 
Leyden Museum, April 1911. 
Notes from the Leyden Museum, Vol. X XXIII. 
