20 Dr. T. Wright on new Species of Echinodermata 
disposed in a single file. The interambulacral areas are about 
five times the width of the ambulacral, and have two rows of 
primary tubercles of moderate size, with from five to six in each 
row. The mammillary eminences on which the tubercles are 
supported are surrounded by areolas deeply excavated out of the 
substance of the test plates ; the margin bounding the areolas is 
raised into a ridge on which a distinct row of close-set granules is 
disposed, so that each tubercle is thereby separated from its fellow; 
the elevation of the marginal ridges produces a zigzag depression 
down the centre of the areas, which is covered with a small 
close-set granulation. The mouth-opening is small and circular, 
and lies in a slight depression; the apical dise is absent in all 
the specimens that have yet been found. The crenulations on 
the mamme are small, but distinct, and the tubercles are of 
moderate size and not deeply perforated. 
Affinities and differences.—This Urchin has many affinities with 
C. coronata, Goldf., and C. propinqua, Minst., and has been cata- 
logued as the former by some authors ; it is therefore important 
that we should point out the diagnostic characters by which it is 
distinguished from them. In both these corallian forms the am- 
bulacral areas have four rows of granules, whilst in C. Bouchardi 
there are only two rows. From C. propinqua and C. coronata 
it is further distinguished by having more rows of primary 
tubercles in the interambulacral areas, in having the areolas 
smaller and more deeply sunk, the tubercles proportionately 
smaller, and the marginal circle of granules smaller and set 
closer together. With C. marginata, Goldf., it has some affinity 
in the excavated style of its areolar spaces, but it is distinguished 
from this beautiful form in having the tubercles smaller and 
more numerous. In C. marginata the ambulacral areas moreover 
are broader and more prominent, and they support four rows of 
small granules, whilst in C. Bouchardii there are only two. With 
C. elegans,Goldf., it has no resemblance whatever ; it belongs there- 
fore to a different group of Cidarites than these foreign corallian 
forms. From C. Fowleri, nobis, it is distinguished by having 
narrower and more deeply concealed poriferous avenues, fewer 
. primary tubercles in the interambulacral areas, and deeper exca- 
vated areolar spaces with a more elevated marginal rim around 
them: these characters serve to distinguish C. Fowleri from 
C. Bouchardii at a glance, and the same diagnostic traits separate 
it from C. Edwardsii, nobis. 
Locality and stratigraphical range.—We have found this spe- 
cies in the Pea-grit of the Inferior Oolite of Crickley, Leck- 
hampton, and Birdlip Hills, Gloucestershire, but have never met 
with any traces of it in the Upper Ragstone beds so rich in 
Urchin forms. Some separate plates collected from the Bradford 
