from the Island of Malta. 63 



in our specimen differs from the Echinus e Messana of that 

 author, who has figured only one large tubercle on each plate 

 of that form. From E. 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 

 Yflths 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 T 7 <jths 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 



