••'--285 
THH 'MEDITERRANEAN • NATURALIST 
the first group are obtainable from indefinite mix- 
tures. It is this latter point that is undoubtedly the 
true key to this enigma of the different results in 
nature, and in the laboratory. 
It will be convenient to take up the principal 
rock-forming minerals one by one and compare 
their occurrence in nature with their reproduction 
artificially. 
PiridMe Jwas obtained, (l)amongst other methods) 
by recuit, at a white-red heat, of the elements of a 
basalt, exactly identical in all characters with what 
occurs in nature. This mineral occurs naturally in 
two forms. The first are irregular nodular masses 
found as bombs, or entirely enveloped in the lava. 
From their large size they must have required a 
long time to crystallize, which took place in all 
probability before extrusion of the magma. They 
no doubt, resulted in some cases by actual crystal- 
lization from the igneous matter: but I believe, by- 
far the larger part are nothing more than a very ad- 
vanced metamorphism of a dolomite; for amongst 
the ejected blocks of Monte Somma or Rocca- 
monfina we may obtain all gradations between the 
original sedimentary rocks of these masses of pure 
olivine. The most common form, in a petrological 
point of view, is the disseminated grains that often 
go to make up a rock These are seen to be nearly 
always one of the first conversions of the amorphous 
paste into formed material. Yet the actual condi- 
tions suitable to its crystallization are not quite 
1 1'jvqve and M. Levy. Bxll. Soc. Min. 1881 , 
t. iit., p. 275. 
1. Indigenous birds. 
No 
clear; for we find lavas ejected from the same volca- 
no abound with it sometimes, and at 1 Others it is 
quite difficult to find. So far as my observation go, 
it favours the basic: rocks of fine-grained .structure, 
and especially those that have cooled quickly 'from 
a very high temperature, although it seems capable 
of increasing in size during- slow' cooling from a 
very high temperature, in consequence of the 1 lava 
stream being very deep. This is the case with some 
very coarse lavas of Vesuvius, such as that-of Pompei 
and Cisterna, which contain some crystals a centi- 
meter long. 
(To be continued) 
The Birds of Malta. 
In view of the interest that has befen lately ['ma- 
nifested in the ‘‘Bird v. Insect 1 ' question the: fol- 
lowing list showing the number »of birds indigenous 
to the Maltese islands, and- the niodt comnion of 
the non-indigenous species has been compiled. 
The remarks oh the' food that have been ap- 
pended have been taken from the works' of such 
authorities as J. E. Halting, F.Z.S., and Prof. 
Saunders. The number of species of birds 'that 
actually visit the islands in the course of ‘ a year 
is between 250 and 260, and 6f these a very great 
number are insectivorous. In the following list, 
we have chosen only those birds that are consid- 
ered to be the most common. It represents 45 
species. 
Tinnunclus alau- 
darius 
Columbia livia 
Corvus monedula 
Petrocincla saxa- 
tilis 
Sylvia conspicii- 
lata 
Lanius Rufus 
Passer sallcicola 
Puffinus cinereus 
Puffinus auglorum 
Thalassidroma 
pelagica 
Kestrel 
Rock pigeon 
Jackdaw 
Blue rock thrush 
Spectacled war- 
bler 
Woodchat shrike 
Spanish sparrow 
Cinerous shear- 
weter 
Manx shearwater 
Storm petrel 
Maltese 
Spagnolett 
Hainiem tal gebel 
Ciaula 
Giambublu 
Bufula tal harrub 
Cacciamendula 
Ghasfur tal belt 
Ciefa 
Garni 
Cangiu ta Filfla 
Remarks 
Feeds largely or beetles and other insects. 
Grain, snails, and weeds. 
Chiefly of insects and their larvae & worms. 
Earthworms, snails, insects, :J ancl 1 their 
larvae and wild berries: " 
Largely on insects, especially Tipulae, 9 
species. 
Largely on beetles and all kinds of insects, 
especially caterpillars. 
Grain, and a small percentage of insects. 
Surface fish, offal and small cuttle fish. 
Do. Do. Do. 
Crustaceans, molluscs, small fish &c. 
1 
2 
3 
4 
5 
6 
8 
9 
10 
