770 CONTRIBUTION TO AUSTRALASIAN OLIGOCH^ETA, I., 



segments x.-xiv., these metameres increasing in diameter as they 

 approach segmeut xii. The area of segments xii.-xiii. constitutes 

 a well marked girdle, the clitellar region being confined to these 

 segments. The line of division between these two segments is 

 not distinct, and even in longitudinal sections the septum some- 

 times appears to be absent, although the ganglionic aggregations 

 in the ventral nerve-cord make the distinction clear enough. In 

 the region of the body anterior to segment x., the lines of division 

 between the various metameres are marked by perfect grooves, 

 but in the postclitellar region the lines of division become less 

 and less important as they approach the posterior extremity of 

 the body. The pros torn ium is semicircular in contour, measuring 

 012 mm. in the killed specimen from the anterior extremity to 

 the groove separating it from the buccal segment. 



Seke. — Yentral setae are absent in the first or buccal segment 

 as in Qligochaeta in general. No traces of them could be found 

 in the clitellar region (segments xii.-xiii.) after careful examina- 

 tion of specimens treated in various ways. In all the other 

 segments there are present two fascicles, which are situated in 

 the latero-ventral regions of the body, each containing a pair of 

 setae. The setae are exceedingly small in the anterior region, but 

 gradually increase in importance, so that behind the clitellum 

 they become very well developed. 



The paired setae of the latero-ventral fascicles are sigmoid in 

 shape, with no feebly expressed noduius, those in the posterior 

 regions being more strongly curved than the setae of the anterior 

 regions of the body. In each bundle one of the setae exceeds the 

 other in length, the respective measurements being - 08 mm. and 

 007 in the middle region of the body, the shorter one being 

 slightly more strongly curved at its free extremity. In the 

 anterior region of the body the setae become shorter and shorter 

 as they approach the buccal segment. One seta in each bundle 

 has a simple extremity, the other possessing a notch on the 

 convex side of the curved portion near the free extremity. 



The dorsally situated setae occur in segments xxxi.-xliii., are 

 long and slender, and for some time escaped detection in the 



