SOME LITTORAL OLIGOCH ATA OF THE CLYDE. yl 
they are regularly two per bundle in both series throughout the body ; three were noted 
once only, one occasionally. 
There are no peptonephridia. Septal glands occur in the usual segments, those of 
iv. and v. being single, bulky, and situated dorsally over the cesophagus ; in segment Vi. 
there is a pair, elongated and extending a considerable distance backwards (Pl. I. fig. 9). 
The esophagus, narrow in the region of the septal glands, is wider in segments vil.-1x. ; 
it narrows again in the genital region, and widens to become the intestine in segment 
xiv. ‘The wmtestine is not constricted at the septa. The chloragogen cells are note- 
worthy ; they are large, with large refractile oil globules; in sections they appear 
colourless, without brown or yellow granular pigment, and very markedly vacuolated, 
as if their contents had been dissolved out; there are several or many large vacuoles in 
each cell. They are present here and there in segments v. and vi., though they can 
hardly be said to begin before vii.; they are numerous and distinct in viii.—x., though 
a b 
Fig. 8.—a, seta of Enchytrxus nodosus. 
b, a seta of Enchytreus nodosus showing 
a slight double curvature. 
not completely covering the cesophagus, and in particular they leave the tract of the 
dorsal vessel uncovered ; they are absent in the genital region, and begin again, thence- 
forward forming a complete investment of the intestine, in segment xiv. 
The dorsal vessel begins at the level of the setee of seement xii., and bifurcates at 
the junction of the prostomium and first segment. The b/ood is colourless. 
The celomic corpuscles are flat, circular, and, as measured in sections, are from ‘014 
or less up to (019 mm. in diameter. They are opaque by transmitted light, with a 
clearer nucleus; the opacity is due to numerous refractile oil-like corpuscles crowded 
together so as to fill up the whole body of the cell. 
The nephridia (fig. 9) begin in segment viii. The ante-septal portion is of consider- 
able size, somewhat ovoid in shape, about one-third as long as the post-septal ; the open 
mouth of the tube is clothed with fine cilia, and its margin projects on one side as a short, 
overhanging process; cilia beat in the tube in a downward direction, and the tube 
undergoes many windings before it reaches the level of the septum. A narrower neck 
connects the ante-septal with the post-septal portion; the latter is elongated, narrow 
