1914.] J.Stephenson: Oligochaeta. 405 



the level of the neighbouring annuli ; it extends across the middle 

 line from just outside the line 6 to a corresponding point on the 

 other side. In If, on the left side only, is a small ridge of appa- 

 rently the same character, its centre just internal to the line a, 

 its length a little greater than the distance ab. 



On the dorsal surface of the clitellum and the anteclitellial 

 region there are a number of minute black dots, simulating setae ; 

 they are sometimes arranged in rows, with fairly regular intervals, 

 round the middle of the segment; they are also found numerously 

 and irregularly scattered quite out of any possible position of 

 setae. 



Septum s is much thickened, of conical form with apex back- 

 wards; f is extremely thick, and is also elongated to form a cone, 

 so that its attachment to the oesophagus is at the level of the 

 spermathecal apertures, i.e. furrow I. Septa y and & are absent; 

 l-TT are much thickened; \\ is not a definite septum, and is re- 

 presented probably by the connective tissue between the testis sac 

 and vesicula seminalis. Behind this the septa are all thin. 



The oesophagus is thick and muscular. A hard, almost glo- 

 bular gizzard lies in the interval between septa \^ and ^, behind 

 the level of the spermathecae. A pair of large dark-brown 

 lateral swellings of the oesophagus occur in segment xii ; their 

 transverse striation denotes their vascularity^ during life. The 

 intestine begins in xvi, but it is at first compressed between the 

 prostates. 



The last heart is in xiii. That in xi is deeper in position and 

 smaller, or at least less conspicuous, than those of neighbouring 

 segments; and as it has to be searched for, ma}' cause temporar}^ 

 confusion in the numbering of the segments, especially as the 

 corresponding septum is absent. 



The excretor}^ system consists of micronephridia, very numer- 

 ous and of moderate size, scattered over the body-wall. 



The testis sacs are in segment xi, attached fairly firmly to 

 septum TT, but capable of being separated without injury. Each 

 is apparentl}^ separate from its fellow, but is attached to the 

 corresponding vesicula seminalis. When opened, the sac is seen 

 to contain a large, tightly packed and iridescent funnel. The vas 

 deferens leaves the testis sac po.steriorly, and can be traced for 

 some distance; it disappears on or in the body-wall, but becomes 

 distinct agaii posteriorly, where, slightly thickening, it passes to 

 the outer side of the terminal portion of the prostatic duct, just 

 behind which it ends, after finally swelling to form a sac-like dila- 

 tation. 



The vesiculae seminales are a pair of granular-looking, 

 3^ellowish, laterally compressed masses, at the sides of the ali- 

 mentary canal in segments xii-xiv. The^^ are attached to the 

 sides of the alimentary canal in xii ; their margins are lobed, and 

 the anterior end of each is covered with numerous minute white 

 (nephridial?) loops. 



