from the Island of Malta. 63 
in our specimen differs from the Echinus @ Messana of that 
author, who has figured only one large tubercle on each plate 
of that form. From £. Scilla it is certainly distinct, as we 
know of no Urchin that is common to the cretaceous and 
tertiary rocks. The test is circular, much depressed on the 
upper surface and flat below; the ambulacral areas are almost 
;;ths of an inch in width at the border, where we count 
four rows of tubercles; the marginal rows are very uniform in 
size and arrangement from the mouth to the disc; the two in- 
ternal rows are smaller, and continue from the border to the 
mouth ; one of these extends a short distance on the sides, but 
on the upper half of the areas there are only the two marginal 
rows: the interambulacral areas are {/>ths of an inch in width 
at the border ; there are eight rows of tubercles at this point 
and onwards towards the base, they are nearly of the same size ; 
but, from the border to the apical disc, the second row, from 
the ambulacral areas, alone possesses the size the tubercles have 
at the border; the tubercles in the others diminish in size, and 
disappear as the areas become narrower ; above, we find only 
two marginal tubercles of the primary size, and internal to 
these, a few of secondary magnitude irregularly set: all the 
tubercles are raised on mammillary eminences, with areolas 
around their bases, and numerous large granules fill up all the 
intervening spaces, so that the surface of this Echinus has a 
very tuberculated appearance. The poriferous avenues are on a 
level with the test; the pores are arranged in triple oblique 
pairs ; between each pair there is a slight elevated ridge; every 
two ridges of each triple oblique pair of holes is connected by 
another ridge, which runs at an angle of 45° to them; by this 
arrangement the poriferous avenues exhibit a curious zigzag 
character through these little elevations of the test in the line 
of the pedal pores. The base is flattened, the mouth-opening 
is large and decagonal, and the jaws and teeth are narrow and 
much curved inwards; the apical disc is absent in all the speci- 
mens we have examined ; the space for the same is, however, of 
moderate size. 
Affinities and differences.—This species may be distinguished 
from Echinus Serresii, Desmoul., from the Molasse de Provence, 
in having larger tubercles, with less granulation at their base, 
and the absence of the zigzag ridges between the pairs of pores: 
from Echinus dubius, Agass., another tertiary species from the 
Molasse of Villeneuve in Provence, it is distinguished by the 
more uniform size of its tubercles, the depression of the upper 
surface, and the zigzag ridges of the poriferous zones. 
Locality and stratigraphical range.—It was collected from bed 
No. 1, the Gozo marble, Malta, where it is not uncommon. We 
