Australian Eartliwoi'mx. 24:1 



(7) The Large Intestine forms the hist purt of the alimentary- 

 canal, reaching to the end of the body. It varies in the size of 

 its lumen in the different specimens, 1)ut is easilj- distinguished 

 from the oesophagus bv its larger lumen and its lateral 

 sacculations. 



A very noticeable feature seen in the dissections of some of 

 the species, such as M. dorsalis, M . fielderi and B. tanjilensis, is 

 the presence of a large number of nephridial tubes attached 

 ventrally in the region of the pharynx. They are in the form of 

 bunches, one each side of the pharynx, and have generally been 

 considered as " peptonephridia." The latter have been defined 

 by Beddard as nephridia, opening into the anterior section of 

 the alimentary canal, and functioning in relation to digestion. 

 So far, however, as I have examined I have found them opening 

 to the exterior, not into the canal. I cannot, therefore, regard 

 them as peptonephridia, but simply as a specialized group of 

 nephridia, the meaning of which is not clear. 



B. — Microscopic Structure. 



As regards the microscopic structure of the alimentary canal, 

 we have much the same structure in the corresponding parts 

 of the different species. 



The presence of a cuticle is easily seen as far back as the 

 end of the gizzard, and also in the intestine, but in the 

 oesophagael region it is difficult to determine its existence. 



I have only found cilia in certain restricted areas, viz., in the 

 hinder portion of the oesophagus in the two species, Megascolex 

 dorsalis and Bipororhaeta bakeri, and in the calciferous glands 

 of Cryptodrilus .^accarius. They may be present in other re- 

 gions besides these, but I have not examined enough specimens 

 to state definitely the ciliated regions. 



(1) The mouth leads into the buccal cavity. 



(2) The buccal cavity is lined with a cuticle and large 

 columnar cells. Connective tissue fibres stretch across the body 

 space from the cavity wall to the body wall. 



(3) The pharynx is lined by cuticularized columnar epithelium, 

 which is folded dorsally and sends ramifications up into the 

 dorsal mass. In sections the mass is found to consist of an 



llA 



