W. \V. Smith. — On Neir Zealand Eart'mvorms. 157 



Earthworms vary greatly according to the soil aud situa- 

 tion they inhabit. At the Kangitata Gorge Octochcetus multi- 

 porus and Acanthodrilus novce-zealandia^iisanihQiv maximum 

 size. The site they inhabit is composed of a deep, rich, black- 

 ish loam, about lOin. in depth, resting on a substratum of 

 3'ellow clay. The worms, when taken out of the soil, are of 

 a reddish colour ; whereas at Ashburton and other districts 

 where I have obtained them on the plains they are bluish- 

 white, and occasionally of a yellowish tinge. At Ashburton 

 they are smaller than individuals inhabiting moist land nearer 

 the ranges. At one place where we dug out cocoons of 0. 

 multiporus we have occasionally obtained short, stout forms 

 of that species with a largely-developed clitellum. Acanthodri- 

 lus novce- Zealand ice, and the smaller species annectens, are 

 very variable in size and colour in several districts where I 

 have collected them. The known species of endemic Acantho- 

 drili comprise a gradational series not known to exist in other 

 genera in any single zoological region, while their prototype, 

 Deinodrilus henhaml, is also endemic. A. roses is the most 

 constant form in colour and size I have met with in the 

 endemic Acantliodrlli. 



Exotic earthworms, acclimatised in New Zealand, are ex- 

 tremely variable. Fully-matured individuals of Lunibricus 

 terrestris are plentiful, ranging from lin. to 6in. in length ; 

 the former occur in poor soil, the latter in decayed or decay- 

 ing vegetable matter. I, however, need not particularise any 

 species, for, although exotic earthworms are rapidly invading 

 cultivated districts in hordes, they all attain their maximum 

 size in heavily-manured gardens, and especially in accumula- 

 tions of decayed vegetable matter-''. In the case of Microscolex 

 viodestus, Eosa, 1 think it probable that the extreme dispropor- 

 tion in size and variation in colour of individuals of the species 

 may be the only cause for supposing them to belong to two 

 distinct species. The variability of earthworms has been 

 almost overlooked by authors when describing new species, 

 more especially in the genus Lumhricus and the allied genera. 

 The Eev. Mr. Friend's " Eevised Synonymy of British 

 Worms"! should be specially acceptable to naturalists in un- 

 ravelling much of the confused synonymy of British worms. 



* When referring to the rapid accumulation of mould ejected by worms 

 living in the forest-clearings in the Grey Valley; Wcstlancl, I should have 

 stated that it is the work of introduced worms. The rich humus covering 

 the bottom of the moist forest, when newly cleared, is extremely nutritious 

 to worms. The subsequent compression of the loose forest mould by cattle 

 compels them to eject their castings on the surface. The nutritious food 

 and moisture in the forest-clearings are the chief causes of the enormous 

 increase of exotic worms in these places. 



t Loc. cit., p. 313. 



