78 Dr. T. Wright on Fossil Echinoderms 
Description.—The specimen before us is so much injured on 
the dorsal surface, that we are unable to give a detailed descrip- 
tion of this species, which appears to be not uncommon at Malta. 
The ambulacral areas are narrow; the pores lie in contracted 
zones, and the pairs are unconnected by sulci; the avenues ex- 
tend more than half-way down the sides of the test ; the dorsal 
surface is elevated and convex, rounded before, and sloping gra- 
dually from the vertex to the posterior border; the apical disc 
is very excentrical, and placed near the anterior border ; the cir- 
cumference of the test is of an irregular oblong figure, round 
before, flattened on the sides, and produced behind : the base is 
undulated by the elevations of the interambulacra and the de- 
pressions of the ambulacral areas; the single interambulacrum 
is prolonged backwards, and is truncated at the sides and at the 
posterior border, which gives it a caudate form. The mouth 
is nearly central, and is sunk in a deep depression; it is 
transversely oblong, and is surrounded by five oral lobes, 
having five petaloidal depressions of the ambulacral areas, with 
three pairs of pores in each petal between them; the anus is 
larger than the mouth-opening, and is situated at the inframar- 
ginal border of the caudate process of the interambulacrum ; it 
has a transversely oblong form, and is more convex before than 
behind. The Urchin figured by Grateloup is much larger than 
the Maltese specimens that have come under our notice ; but 
the central mouth-opening and the form of the interambulacrum 
induce us to think that it is only a gigantic variety of E. Richard, 
and not EF. Kleinii, as supposed by Desmoulins. The identity of 
this species with Klein’s Scutum ovatum Issyaviense may or may 
not be correct, as the figures of fossils in that work are not in 
every case to be depended on. : 
Affinities and differences.—E. Richardi has some resemblance 
to E. Kleinii, but the narrow ambulacral areas, the flattened 
sides, and produced caudate interambulacrum in E. Richard 
afford points of distinction by which these allied forms may be 
readily distinguished from each other. In E. Kleinii the base is 
more concave, the mouth nearer the anterior border, and with 
larger oral lobes than in E. Richardi. The dorsal surface presents 
other points of difference: in EZ. Kieinii the posterior half of the 
test is the most elevated, whilst in H. Richardi it slopes rather 
abruptly downwards from the vertex to the truncated posterior 
border. 
Locality and stratigraphical range.-——It was collected from bed 
No. 2, at Malta; the specimen before us is the only one in 
Earl Ducie’s cabinet. The Geological Museum in Jermyn Street 
possesses an interesting series of this form, which are all from 
the same island. Grateloup found the large variety at Dax, in 
