Further Descriptions of Australian Eartlavorms. 33 



Setae regulai'ly arranged ; the two of each ventral pair close 

 together ; the two of the outer pair widely separate ; the distance 

 between them being equal to that between the lower of the two 

 and the ventral pair. 



Male pores on segment 18 at the level of the interval between 

 the setae of the ventral pair. 



Oviduct pores on segment 14. 



Spermathecal pores two ; intersegmental ; at the level of the 

 ventralmost setae between segments 6 and 7, 7 and 8. 



Dorsal pores present. The first visible one between segments 

 12 and 13. 



Nephridiopores indistinguishable externally. 



Alimentary canal. Gizzard in segment 5. The walls of the 

 canal in segment 16 are white and swollen, but there is no 

 sharply pinched off portion as in the case of the calciferous 

 glands of other species. Large intestine commences in segment 

 18. 



Blood vascular system. Dorsal vessel single. Hearts in 

 segments 8-12. A strongly marked plexus of blood vessels 

 surrounding the alimentary canal in segments 3-7, the dorsal 

 blood vessel breaking up in the latter. 



Excretory system.^ Two nephridia on each side of the 

 segment. 



Reproductive system. Testes, two pairs in segments 10 and 

 11, into which also the ciliated rosettes open. 



Spermiducal glands, small, coiled, tubular, in segment 18. 



Sperm sacs, racemose, attached to the posterior wall of segment 

 9, and the anterior of segment 12. 



Ovaries in segment 13, the oviducts opening into the same 

 segment. 



Spei^mathecae in segments 8 and 9. Each consists of a long 

 sac with two short tubular diverticula. 



1 In consequence of the presence of three nephridia in each segment in certain forms 

 described by Mr. Fletcher and myself, Mr. Beddard has placed these in a new genus, to 

 which he has given the name of Trinephrus. It may subsequently be advisable to erect a 

 new genus for the reception of the present and one or two other species characterized by 

 the presence of two nephridia on each side and to which the name Dinephrus may be 

 given. Meanwhile pending an examination into their microscopic structure, which is now 

 being conducted and the results of which will shortly be published, I have retained the 

 species in the genus Megascolides. 



