354 MR. F. E. BEDDARD ON [May 3, 



each of the ventral bundles. The number of setse per bundle dimin- 

 ishes in the posterior segments, and they become mingled with 

 sigmoid setae. In the seventh segment both setae in one of the 

 ventral bundles were sigmoid, as was one of the two setae of the 

 dorsal bundle. The sigmoid setae occur, therefore, in both dorsal 

 and ventral bundles ; I was, however, quite unable to detect any 

 bifurcation at the free extremity of these setae, and I examined them 

 with the highest power at my disposal (Zeiss's F lens with eyepiece). 

 I could not detect the nephridia. 



In the colourless integument and in the presence of two kinds of 

 setae this species evidently offers a transition to the Naidomorpha. 



iv. On Clitellio and Limnodrilus. 



These two genera, usually regarded as distinct, have been united 

 by M, Vaillant in the recently published third volume of the 

 *Anneles ' in the ' Suites a Buffon.' 



M. Vaillant considers that the alleged absence of a prostate in 

 Clitellio is not a sufficient difference. 



As a matter of fact, my own paper ^ upon Clitellio showed other 

 points of difference besides the absence of the prostate ; the main 

 distinction between the two genera, in addition to the want of a 

 prostate, is the existence of two pairs of perivisceral trunks, which 

 are specially enlarged and are contractile : I did not refer very defi- 

 nitely to their contractility in the paper cited, but I have since re- 

 examined the species Clitellio arenarius and find that these dilated 

 trucks are contractile, one pair contracting before the other. Now 

 the fact of the existence of contractile trunks does not distinguish 

 Clitellio from Limnodrilus. Limnodrilus has also two pairs of con- 

 tractile periviscerals, but only one pair of these are dilated ; whereas 

 in Clitellio both pairs are wide tubes. This difference, at any rate, 

 applies to the species oi Limnodrilus known up to the present. 



I take this opportunity of mentioning that Clitellio arenarius 

 has, like Limnodrilus, a supra-intestinal blood-vessel. But I could 

 find no integumental blood-capillaries such as are found in Limno- 

 drilus. I looked for them very carefully, of course in living worms. 



So far, therefore, my observations have rather tended to accentuate 

 than remove the differences between Clitellio and Limnodrilus. 



I have, however, found in a species of Limnodrilus an intermediate 

 form between Clitellio and the typical Limnodrilus. This species 

 is from New Zealand ; I have already ^ recorded its occurrence m. 

 the South Island, though I was in error in stating that it presented 

 no differences from the European species. 



As a matter of fact, this New Zealand Limnodrilus has, like Cli- 

 tellio, two pairs of greatly dilated hearts in segments viii. and ix. , 

 there are no reasons for disbelieving that these wide trunks are 



^ " On certain Points in the Structure of Clitellio (Olaparede)," P. Z. S. 1888, 

 p. 485. 

 =" "On the Oligochaetous Fauna of New Zealand, &c.," P.Z. S. 1889, p. 381. 



