358 Dr. Fourtaw—Echinid Fawna of the Neogene. 
Wright, which is also found at Malta, in Corsica, and in Sardinia. 
The existence of Spatangus corsicus, Desor, in Egypt, is not definitely 
established, but S. pustulosus, Wright, can be mentioned without 
hesitation. 
Maretia (sensu lato), Gray, is represented by two forms peculiar to 
Egypt, I. fuchst, Oppenheim, which appears to be a simple mutation 
of M. tuberosa, Fraas, which, in its turn, might in’ reality only be 
a variety or race of ‘lu. ocellata, Defrance. I have not thought it 
necessary to maintain the genus Memipatagus, Desor, the primary 
tubercles of the Egyptian forms have deeper ‘‘scrobicule”’ than 
those of the present-day Maretia. These ‘‘ scrobicule”’ in reality 
only produce swellings in the interior of the test and not the 
‘Campulle’”’ so characteristic of the genus Lovenia, Desor. If the 
M. ocellata from the Miocene of the neighbourhood of Bordeaux 
have, as says Lambert, scrobicular “‘ ampulle”’ in the interior of the 
test, the question will arise whether they should be separated from 
the genus JMaretia, and also if they agree with Defrance’s type, 
which came from the Rhone basin, and with the Swiss neotype, the 
only one figured to this day by Agassiz and de Loriol, who never 
made any reference to the presence of these ‘‘ampulle”’ in the 
specimens they studied. 
Two Miocene forms of Zoventa are new and peculiar to Egypt. 
Finally, the genus Lchinocardium, Gray, is represented by three 
species; two of these are Miocene, of which one is £. depressum, 
Agassiz, and the third is of Pliocene age. 
As regards geographical distribution, we have been able to note 
35 forms common to Egypt and the western basin of the Mediterranean, 
including 9 Miocene Clypeaster. Of these forms 12 are present in 
Algeria, 21 are found in the Miocene of Italy and the Italian islands 
of the Tyrrhenian Sea, 8 exist in Malta, and 14 in the Neogene of 
the Rhone basin in France, and up to the present 40 apes to be 
special to Egypt. 
It is interesting to lay special stress on the presence in Egypt of 
a representative of the genus Lepedopleurus, which till now has been 
exclusively Indian, and of a form very near Brochopleurus stellulatus, 
Duncan & Sladen, also from India. 
From the paleobiological point of view (leaving aside the Pincers 
Echinids, which have only been found in Egypt in a single locality 
near the pyramids of Giza) a quasi-independence can be noted between 
the two Egyptian Miocene basins to the east and west of the Nile 
Valley respectively, which only have five forms in common and three 
species, represented by varieties in each basin. Of species with 
Indian affinities, one is in the eastern basin and the other in the 
western. It should be noted that the Lower Miocene is represented 
in these two basins by two forms common to both: Scutella zittelv, 
Beyrich, and Schizaster legraint, Gauthier. 
We may explain this dissimilarity of fauna by the difference of the 
facies in the two basins. In fact, the Middle Miocene deposits of 
the western basin are nearly exclusively formed by a mass of very 
ferruginous and siliceous hard limestones, interbedded with more or 
less sandy layers and overlying a detrital formation of ferruginous 
