from the Island of Malta. 6] 
always in small detached beds of inconsiderable extent, which 
do not extend into the interior of the island. The deposits of 
Bonifacio and Saint-Florent were the only ones visited by M. 
Collomb*. The rock is a light-coloured limestone, sometimes 
white and soft, or hard and cherty, and contains an abundance 
of small quartz pebbles derived from the decomposed granite. 
B. Description of the Fossil Maltese Echinoderms. 
Cidaris Miletensis, Forbes MSS., n.sp. Pl. IV. fig. 1 a-c. 
Test oblately spheroidal, much depressed at both poles; am- 
bulacral areas undulated, depressed in the centre, with an 
elevated marginal row of close-set tubercles on each side of 
the areas ; poriferous avenues of the same width as the areas ; 
interambulacral areas rather prominent, with two rows of 
primary tubercles, about six in each row; mammillary emi- 
nences large, each with a circle of boundary granules ; spines 
nearly the diameter of the test in length, tapering from the 
base to the apex ; mouth-opening very large. 
Dimensions.— Height =8,ths of an inch; transverse diameter 
15, inch. 
Description.—This is a very rare Urchin in the Maltese beds. 
It has an oblately spheroidal figure, and is much depressed at 
both poles; the ambulacral areas, with the poriferous zones, are 
gently undulated ; they measure together ths of an inch in 
width; the areal band is depressed in the middle, and its 
elevated margins are covered with two rows of large equal-sized 
close-set granules ; internal to these are two rows of much smaller 
granules, and down the centre is a depressed furrow: the pori- 
ferous avenues lie likewise in depressions, bounded internally by 
the marginal granules of the ambulacral areas, and externally by 
the encircling granules of the primary tubercles: the inter- 
ambulacral areas are 34 times the width of the ambulacral ; they 
form rather prominent convex portions of the test, with from 
five to six rows of primary tubercles in each of the two rows of 
these areas: the areolas are large and prominent, the summits 
are smooth and without crenulations, and the tubercles, which 
are proportionately large, and with a very small perforation in 
their summit, stand well out from the body: a circle of larger 
granules surrounds the base of the mammillary eminences ; 
these circlets are each complete in the two superior tubercles, 
but one series is common to two tubercles in those near the 
mouth ; the boundary im all, however, is defined, as none of the 
* Bull. de la Soc. Géol. de France, tom. xi. p. 67 et seq., 2 série. 
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