Hzcron.—On the Dolphins of the New Zealand Seas. 207 
poisoned. It descends into Wellington during hard weather, and if the 
Empire City is not spared, we must look for a like visitation from time to 
time. 
Some say that the colour of our rat is not dark enough to admit of the 
opinion that it is a “ Kiore Maori.” But the Mus rattus is said by a dis- 
tinguished naturalist to change from black to grey—very old individuals 
becoming decidedly hoary (Trans., vol. iv., p. 184). We should hesitate, 
therefore, before pronouncing positively as to the classification of a rat from 
colour alone. Anatomical structure, size, and habits seem to be more im- 
portant elements to consider. 
8. As to what it is that causes the death of so many of our visitors— 
for their corpses in various stages of decomposition lie about our properties 
everywhere—there need be no diffieulty. Their enemies are numerous. 
Every man's hand is against them. Dogs and eats worry them about our 
houses. Native birds pounce upon them in the open fields. Their more 
powerful congeners—the brown rats—wage war against them 4 outrance. 
A survey party in Motueka the other day dug out a rat hole, and found 
therein a Norwegian female and her young, and by their side about twenty 
skins and other remains of the smaller rat. Besides these enemies they 
have to contend with disease, probably occasioned by change of food and 
surroundings. Moreover, they do not seem to have the experience or 
eunning of the brown rat as to the avoidance of danger; and as their 
numbers are so great, their slaughter is proportionately wholesale. Between 
them and the brown rats there will of course be a war of races. But the 
black rat, neither in Europe nor here, has ever been a match for the other 
rodent. We shall not have these interesting strangers amongst us long— 
already they are diminishing in numbers, and soon they will probably retire 
to their mountain fastnesses as mysteriously as they descended upon us. 
If we did not weleome their coming, I think without doubt we shall speed 
the parting guests. 
Art. XXIII.— Notes on the Dolphins of the New Zealand Seas. 
By James Hector, C.M.G., M.D., F.R.8. 
[Read before the Wellington Philosophical Society, 26th November, 1884.] ji 
Ix 1872* I collected all the information at my command respecting the 
dolphins that frequent our coasts, and distinguished the species according 
to the mode of classification adopted by the late Dr. Gray in his catalogue. 
> Trane. N.Z. Inst., vol. v., art. xix. 
