NEW GENERA AND SPECIES OF EARTHWORMS. 249 



the neighbourhood of the termination of the median sac 

 already described. These sacs really form part of the sper- 

 matothecae, with which they are connected as shown in the 

 figure (fig. 9). At a distance of half an inch or so from the 

 caecal extremity each sac comes into close relations with the 

 posterior part of the large spermatothecal sac ; at these points, 

 which are quite close to the external orifice of the sac. there is 

 a communication between the two. Each sac then passes 

 forwards in close contact with the body-wall, and is slightly 

 constricted at the septa. The two sacs (right and left) appear 

 to be perfectly separate from each other, and indeed the 

 muscular terminal sac of the atria intervenes ; but on remov- 

 ing the nerve cord, which fills up the space between them, the 

 two sacs are seen to be joined by about seven narrow bridges, 

 which form a ladder-like arrangement shown in the figure. 

 Two of these transverse connections lie behind the atrial aper- 

 ture, while the remainder lie in front ; anteriorly each sac 

 diverges to one side, and becomes connected with the oviduct 

 and egg-sac. Although the above description of the compli- 

 cated spermatothecal apparatus of Polytoreutus magi- 

 lensis appears to show a considerable difference from Dr. 

 Michaelsen's species, a comparison of my figures (figs. 7, 9) 

 with his (loc. cit., Taf. i, fig. 10) of the corresponding organs 

 in Polytoreutus coeruleus will readily permit of a detailed 

 homology. In both worms the spermatothecal pouches are 

 only incompletely fused ; but the fusion between the origin- 

 ally separate sacs (?) has taken place in a different manner. 

 In Polytoreutus coeruleus the spermatotheca has two 

 pairs of diverticula near to the external orifice; these cor- 

 respond' respectively to the parts lettered b and c in the 

 figure illustrating Polytoreutus magilensis: b still retains 

 considerable traces of the double condition. The unpaired 

 median pouch in Polytoreutus coeruleus, which is con- 

 tinuous anteriorly with the egg-sacs, is nearly completely 

 double in Polytoreutus magilensis. 



It seems probable that the structures spoken of here as 



