124 Transactions. — Zoology. 



occurs in a genus, Plutellus, belonging to quite a different 

 family from America. 



The group of species included in Michaelsen's Notiodrilus 

 is of much wider distribution. 



The genus Acanthodrilus, according to Michaelsen, is con- 

 fined to one species — the original type of the genus — from 

 New Caledonia. Consequently, the worm originally called 

 by Hutton " Lumbricus uliginosus" is now properly to be 

 termed 



Acanthodrilus (Maoridrilus) uliginosus, Hutton (Syn., 

 Acanthodrilus novee-zealandiee, Beddard). 



It may, perhaps, be as well to give a brief account of the 

 external and internal anatomy of this worm, the earliest 

 species of our native earthworm fauna to be named and de- 

 scribed (for we may except Baird's " Megascolex antarctictcs," 

 which has not yet been rediscovered nor sufficiently de- 

 scribed to be recognisable). And, in the interests of our 

 students of biology, I will describe it pretty fully, for there is 

 no general account of our native worms accessible to them, 

 so that they have had to be content with an account of the 

 European earthworm, which differs considerably. Moreover, 

 the account will serve in general for any of our large, com- 

 mon, native worms. 



Length. — This varies, as in most earthworms, between 

 certain limits. When alive it is pretty extensible, reaching 

 to more than 1 ft. in length ; but when preserved the worm 

 measures anything from 5 in. to 11 in. Usually it is Bin. 

 or 9 in. in length, and pretty constantly fin. in breadth 

 posteriorly to the clitellum. The worm retains this breadth 

 for the greater part of the body, tapering rather suddenly 

 to the posterior end, and more gradually to the anterior, 

 which is pointed. 



The number of segments varies from 130 to 230, for, as 

 in other worms, new segments are added posteriorly as it 

 grows. 



The colour of living individuals is not unlike that of the 

 European Lumbricus agrico.a, being a reddish-brown, fading 

 slightly posteriorly, and with a paler and browner clitellum ; 

 but the back is dark all along the body, while the ventral 

 surface is pale. 



The prostomium, too, is like that of Lumbricus, in being 

 prolonged backwards across the dorsum of the buccal segment 

 as far as its hinder limit. 



Each segment of the body, with the exception of the 1st 

 or mouth-bearing segment (hence termed peristomium, or 

 buccal segment), is provided with eight bristles or chaetae 

 (sometimes also termed by the latin equivalent "setae"), 



