THE ZooLocist—DEcEMBER, 1876. 5177 
which are placed in abnormally favourable conditions for their 
multiplication. If in their wild state dangers have to be en- 
countered which to a certain extent diminish their productiveness, 
yet these very obstacles tend to strengthen their vital force. It 
is said that diphtheria is apt to break out among domesticated 
ostriches, and as the number of these mounts up annually we are 
apprehensive lest this complaint may sometimes assume the 
severity of “an ostrich disease,” to the loss and disappointment of 
those who are devoting themselves to ostrich rearing. 
The work of which we give this short notice is appropriately 
illustrated with pictures of various modes of ostrich hunting, and 
with figures, beautifully drawn and engraved, of the ostrich, 
rhea, emu, cassowary and apteryx. It is just the sort of book 
to give as a Christmas present to a young naturalist. Had 
ostrich farming existed when we were young, and had such 
an interesting account of it as that supplied by Messrs. Harting 
and de Mosentbal been -put into our hands, we feel quite 
certain that we should have been fired with a desire to emigrate 
at once to the Cape Colony in order to join in what would 
have seemed to us a most fascinating method of making our 
fortune. 
Morray A. MATHEW. 
November 11, 1876. 
Black Water Rat.—On the 27th of October an adult water vole (Arvicola 
amphibius) was trapped at Keswick, near Norwich, in which the entire fur 
was of a deep black, but with a slight silvery reflection on some of the 
longer hairs of the back; it was caught in a garden, into which it had 
probably strayed from a neighbouring meadow.—J. H. Gurney ; Northrepps, 
Norwich. 
[A black variety of this species, described by Pallas and other continental 
naturalists, has long been known. According to Macgillivray, who described 
it under the name of Arvicola ater, this variety is very common in Banff- 
shire and Aberdeenshire. We have seen specimens from Cambridgeshire, 
and, if our memory serves, from Sussex also, where two or three were 
obtained on the mill-stream at Ratham, near Chichester, by Mr. W. Jeffery. 
Apropos of varieties of the water vole, three white specimens of this species 
have come under our notice, obtained at Newbury, Brighton, and Reading 
respectively.— ED. } 
