POLYCH ATA FROM THE N.E. PACIFIC, 96] 
Text-figure 1. 
A. Chetopterus variopedatus. B. Mesochetopterus taylori. 
Anterior view of median segments. 
al., alimentary canal; cil.gr., dorsal ciliated groove ; fr-, lateral borders ; m2z., 
ventral longitudinal musculature; new., neuropodium ; not., notopodium 
with its acicular setee. 
cells. From this, along the median region, there runs a wedge- 
shaped prolongation (w.), which narrows down in the second 
segment to a median groove. But in the first segment it is 
broad, and the neuropodia are restricted to two narrow lateral 
strips of different appearance. Here, then, each neuropodium 
is a single structure ; in the two succeeding segments the neuro- 
podia are much broader, extending almost to the middle line, 
and are divided into a dorsal and a ventral half, the former being 
slightly smaller and pushea a little forward. Hach contains 
several rows of uncini. There is no indication whatever of the 
fusion of the neuropodia to form a sucker-like median structure, 
which occurs in Chetopterus. A typical uucinus of this region is 
figured in text-figure 3. 
The dorsal surface of the median region is covered by glandular 
epithelium, raised into transverse furrows. ; 
Proc. Zoou. Soc.—1914, No, LXV. 65 
