782 CONTRIBUTION TO AUSTRALASIAN OLIGOCHiETA, I., 



shows affinities sufficiently close to Astacopsidrilus notabilis, and 

 equally well those characteristic features which distinguish that 

 new genus from Phreodrilus and Phreodriloides, so that I deem 

 it worthy of specific rank only. 



External characters. — The colouration is white. The body is 

 spindle-shaped and in general outline not unlike a cigar. It 

 reaches its greatest diameter in segments xii. and xiii., the region 

 of the body between segments ix. and xv. being swollen so as to 

 give rise to a bulging area which is of greatest importance in the 

 clitellar region. Behind segment xv., the body gradually dimin- 

 ishes in diameter. In the anteclitellar region the body is slightly 

 flexed so that the dorsal margin is convex from before backwards. 

 Length 2'8mm.; greatest breadth 06 mm. 



The total number of segments is 46; the anteclitellar segments, 

 as in A. notabilis, are longer than those of the postclitellar region, 

 and the grooves separating them much more strongly pronounced. 



The prostomium is obtuse, its anterior margin crescentic and 

 separated from the buccal segment by a groove. The posterior 

 third of the prostomium appears to be marked off from the 

 anterior portion by a feebly expressed groove. 



The clitellum surrounds the body as a cingulum in segments 

 xii. and xiii.; and, although not by any means as readily visible 

 in an examination of entire specimens as in the case of A. nota- 

 bilis, yet it can be easily made out with the naked eye, especially 

 with the assistance of more dense stain, and consequent differentia- 

 tion of this part obtained by the use of hematoxylin or borax- 

 carmine. 



Setce. — There are in all the segments, except the buccal, seg- 

 ment xii., and the last three segments, two fascicles of latero- 

 ventrally situated seta?. Those of segment xiii., (absent in A. 

 notabilis) differ in no wise from the corresponding setse of other 

 segments. These setae are very minute in the anterior region 

 of the body, but gradually become more important as they 

 approach the clitellar region, behind which they show no marked 

 further or stronger development until they reach the posterior 

 third of the body. In this posterior region they become very 





