774 CONTRIBUTION TO AUSTRALASIAN OLIGOCH^TA, I., 



Commissural vessels of an undulating character connecting the 

 dorsal and ventral bloodvessels were made out in segments iv.-x. r 

 inclusive, and from segment xv., backwards. In the postclitellar 

 region commencing in segment xv., the pouches of the intestine 

 are found to be covered by a network of fine vessels in connection 

 with the commissural vessel; and this is specially interesting as 

 no such plexuses are to be found on the portion of the digestive 

 tube anterior to this. Hence an additional character is found 

 as an assistance in the differentiation between the oesophagus and 

 intestine which is thus clearly seen to commence in segment xv. 



In segment xii., there is found, occupying the greater portion 

 of the body-cavity, a mass of a granular nature which takes a 

 stain with eosin similar to that of the bloodvessels and which, in 

 the unstained state, has the same appearance as the bloodvessels. 

 The thought occurs to one that this mass of granules represents 

 a glomerular structure; but I am at a loss to understand its 

 significance, since, both in transverse and longitudinal sections, 

 the granules under high powers of the microscope appear to be 

 quite free and separate, no mutual connection being made cut 

 between them. Further, I have observed that the granular 

 nature of the epithelial cells lining the spermathecal sac is due 

 to the presence, in their cytoplasm, of granules similar to those 

 above-mentioned; and as the ducts from these sacs run forwards 

 to the posterior wall of segment xii., it is quite possible that 

 some relation exists between these granules, and that the mass 

 of material present in segment xii. has been derived from the 

 epithelial lining of the spermathecal sacs. 



A reconstruction of the blood-system made from a study of 

 transverse and longitudinal sections is to be seen in Pl.xxx., 

 fig. 15. 



Excretory system. — Nephridia occur in pairs, as very complex 

 coiled tubes similar to those of the Tubificidce in general, in most 

 of the segments. No traces of them can be found in the first six 

 segments, nor in segments xi., xii., xiii., in which latter lie the 

 essential reproductive organs and their ducts. No distinct 

 internal funnel or external pores were made out. In examining 



