W. W. Smith. — On New Zealand EartJnvorms. 159 



ishes and changes its chemical nature. The native worms 

 are unable to survive the cultivation of the land, and rapidly 

 disappear from soils where natural or artificial manures are 

 used. It is, however, very different with the introduced 

 species — the more manure and culture the land receives the 

 more rapidly they increase and spread. As alien earthworms 

 take possession of newly-broken-up land they rapidly change 

 its chemical nature from' the original condition. The change 

 is disastrous to the indigenous worms, as they are unable to 

 survive the changed or chemically-altered nature of the soil. 

 Like several other introduced animals, the enormous increase 

 and dispersion of alien earthworms is phenomenal. The last 

 mild, wet winter was very favourable to their increase. After 

 every heavy rain-storm vast numbers were to be seen crawling 

 about on the footpaths and streets, and in gardens and fields. 

 From the 12th August to the night of the 5th September the 

 weather continued very dry. In the evening of the latter date 

 a heavy rain commenced to fall, and lasted until next morning. 

 The storm caused prodigious numbers of worms to rise to the 

 surface. Many of them were swept into the side-channels of 

 the streets in Ashburton, and borne by them to the main sewer 

 flowing along the east belt of the town. Owing to the gratings of 

 several of the side-channels becoming choked, or through being 

 unable to discharge the great rush of storm-water, the worms 

 borne by the channels were left crawling about the grating in 

 barrow-loads. This, nevertheless, represents a small number 

 of the worms that are occasionally carried away by street- 

 channels and other streams during and after heavy rains. 

 They were nearly all Lumhricus terrestris, L. I observed a few 

 only of Allolohophora suhrubicunda, A. turgidus, A. ruhcllus, 

 and A. fostid'us amongst them. 



The numerous watercourses now traversing the Canterbury 

 Plains from the hills to the sea are in many places favourable 

 for the preservation of native earthworms. I have obtained 

 very large specimens of OctocJicetus multiporus dug out of the 

 sides of a water-race flowing through a paddock that had been 

 cultivated for ten years. In many paddocks several yards 

 wide of unbroken native land are left on both sides of the 

 water-races. In these strips of land the native worms are 

 favoured with moisture, and attain to a large size. While 

 staying for three weeks at Mostyn House, near Springston, 

 during July and August last, I w^as able to note the actions of 

 earthworms in the neighbourhood of Lake EUesmere. The 

 soil, although of a light, free nature, is very fertile, and yields 

 excellent crops of grain, grass, and other products of the farm. 

 The eminence on which Mostyn House is built rises about 

 30ft. above the general level of the district, and forms an 

 interesting relic of the sand-drift age in the neighbourhood of 



