846 



CONTRIBUTION tO AUSTRALIAN OLIGOCH^ETA, II., 



worm is to be regarded as representing a new genus. This point, 

 however, must be left over until such time as mature individuals 

 are obtainable for examination. 



The worm is not unlike Phreodrilus mauiensis in general 

 external appearance and dimensions. The specimen of that 

 species described by Benham was also unfortunately immature. 



Body. — Length 17-20 mm.; breadth 0*5 mm. ; consisting of 77 

 segments. Segments v.-xvi. are biannulate, at least on the 

 ventral surface; and this appear ance, though not quite so distinct, 

 is again noticeable in the last thirteen segments. In the inter- 

 mediate segments a faint trace of this biannulation appears at 

 intervals. Prostomium conical, measuring 0*15 mm. from apex 

 to base. No clitellar region can be made out, due to the imma- 

 turity of the specimen. 



Sef.ce. — No dorsal setae can be seen in an 

 examination of the entire individual, nor was 

 I enabled to discern them in a study of 

 sections. It may he that, owing to pressure, 

 they have been broken, since their nature renders 

 them more liable to such an accident than in the 

 case of the ventral setae. Ventral setae are repre- 

 sented by two fascicles, one occurring on the 

 latero-ventral region of each segment except in 

 the case of the buccal segment, where, as in all 

 Oligochseta, they are absent. Each fascicle con- 

 tains two setse, which differ from each other in 

 size, shape, and the nature of the free extremity. 

 In the case of the shorter seta the structure is 

 stouter, more strongly curved, and approximating 

 more nearly to a true sigmoid shape; there is a 

 well expressed nodulus; the extremity is not 

 simple, there being on the convex side of the curve 

 towards the free end a well marked tooth. This 

 igs. 1-2.* form of seta measures 0'175 mm. In the case of 



the longer seta the structure is also sigmoid, but much more 



* Figs. 1-2. — The two types of setos in a ventral fascicle. 



