THE MEDITERRANEAN NATURALIST 
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Name of Species. 
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i S. Africa. 
St. Helena. 
Ascension. 
Atlantic Is. 
Mediterranean. 
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Chiton sicvlus ...... 
„ discrepans 
Philine operta 
Lima inilata 
Area lactea 
Venerupis irus 
Petrie ola lithophaga 
Gaslrochcena dubia. . 
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It is quite possible that most of these species 
may have been carried across the Indian Ocean (1) 
to the Cape in various states of development, 
for we know that a very large quantity of pumice 
thrown into the sea during the eruption of Krakatoa 
in 1883 was drifted in that direction, indicating 
the course likely to be taken by larval and 
pelagic forms or even by adult organisms (like the 
last live of the above species) if attached by a 
byssus to, or burrowing into, floating substances 
like pumice. Passing the Cape they may have 
extended up the West- African side of the Atlantic 
past the Atlantic Islands (2), and so on into the 
Mediterranean, at the entrance of which at Gi- 
braltar, the main strong surface current is from the 
Atlantic eastward, which would of course be fa- 
vourable to the influx of species from that sea. 
As I have before stated, this is all mere con- 
jecture, and we have to assume a starting-point 
somewhere in the East, for which we have no 
grounds. The proposition that species common 
to the Red Sea and the Mediterranean may have 
originated in the East, holds good also in regard 
to three of the four species which I consider suf- 
ficiently different from the Mediterranean species 
to be regarded as distinct. Even if we consider 
them practically identical, as Mr. Cooke does, we 
find that they have as near representatives in the 
(1) We conjecture that the ocean-currents took 
the same direction in bygone days: what grounds 
have we for th s ? 
(2) Vide my reports on the Mollusca of St. 
Helena omd Ascension Island (P„ Z. S. 1890 , pp. 
247,817). 
Indo-Pacific. In the case of the fourth species, 
Tellina isseli, I am not aware that it has been 
found anywhere except in the Gulf of Suez, a fact 
which to some extent confirms its distinctness 
from the Mediterranean T. balaustina , consider- 
ing that all the other species common to the wo 
seas have an enormous distribution. 
In the foregoing observations no reference has 
been made to the light which Palaeontology may 
throw upon the subject of distribution of the spe- 
cies in question. It is true that most of them s 
found fossil in the Miocene, Pliocene, and ot 
Tertiary rocks of Italy, Sicily, &c., a fact - 
would seem to indicate a long establish™ '.m 
in the northern hemisphere. On the oth 
hand, a number of recent Mediterranean arc 
Atlantic forms have already been recorded fr 
the Tertiary deposits of Australia (1); and we me.; 
therefore conjecture that when the Palaeontology 
of Australia and other eastern countries 
been more fully worked out, many more so-called 
European species will be discovered. Such being 
the case, I fail to perceive that the evidence af- 
forded by Palaeontology lends more support to 
any one of the theories of distribution set forth 
than to another. Probably all are wrong. 
Proc. Zoo. Soc. London. 
The Geological Photographs Commi e 
of the British Association and its Wo A 
From the copy of the second report of the ado 
Committee which the secretary Mr. O. V . deli's 
has favoured us with, we note that no efforts have 
been spared to render the work of this important 
branch of the British Association of the highest 
scientific value. Since last year the scope of the 
operations of the Committee has been considerably 
extended and many societies have been induced to 
enter with spirit into the scheme. The object that 
the Committee has in view is, i; to arrange for the 
collection, preservation, and systematic registra- 
tion of photographs of geological interest in the 
United Kinghdom:” and judging from the lists 
that are appended to the report there can be no 
doubt but that the work that is being done will 
prove itself to be of incalculable benefit both to 
(1) R. Etheridge , jun., Gat. Australian Fossils , 
1878. 
