1892] 



SPECIES OF EARTHWORMS. 



669 



be (woodcut, fig. 1) ; these setae are also absent from the xviith and 

 from the xixth segments, or rather they are there replaced by the 

 penial setae. In all the species of Acanthodrilus, on the other hand, 

 which I have been able to examine, the ventral setee are not missing 

 from the xviiith segment, though they are not present on the xviith 



Fig. 1. 



At At 



Segments bearing atrial and sperm-duct pores in a number of Acantbodrilids. 



A. OctochfBtus antarcticiis ; B. Acanthodrilus capensis ; C. Bcnhamia (any 

 species); D. Acanthodrilus smithi ; E. Acanthodrilus novm-zelandice. 

 At. atrial pores ; (^, sperm-duct ]3ores; the groove connecting the atrial pores 

 aud the sette is indicated ; penial setae are omitted in D and E. The 

 segments are numbered. 



and xixth segments, being there replaced by the penial setae ; this 

 is also the case with the genus Octocheetus; in two of the species 

 of that genus at any rate, viz. O. multiporus and 0. antarcticus 

 (woodcut, fig. 1), the ventral pair of setae of segment xviii. are 

 Proc. Zool. Soc— 1892, No. XLV. 45 



