from the Island of Malta. 81 
to the Bristol Institution ; we possess one, through the kindness 
of M. Michelin, from the celebrated Urchin bed of Balistro (Cor- 
sica) ; it is found likewise in the “ Molasse du Cap Couronne prés 
Martigues.” (Michelin.) 
Family Spatancipaz. 
The general outline of the Urchins of-this family is oval, ob- 
long or cordiform, and they satisfactorily exhibit the bilateral 
symmetry of the Echinide. The mouth is anterior, bilabiate, 
and edentulous. The anal opening is posterior and supramar- 
ginal, and is closed by a complicated series of small plates. The 
apices of the ambulacral areas are united at the summit .of the 
test. The anterior smgle ambulacrum has a different structure 
from the antero- and postero-lateral pairs, and is in general lodged 
in a depression of the test, which extends to the anterior border 
forming the anteal sulcus; the test is extremely thin, and is 
covered with small tubercles which support hair-like spines ; 
besides these there are some larger crenulated and perforated 
tubercles which support large spines. There are two or four genital 
pores which are sometimes placed close together, but are in other 
genera apart. The eye-plates are five in number, and are placed 
at the apices of the ambulacra in a pentagonal form around the 
genital plates. We observe on the surface of the test of some Spa- 
tangide, certain delicate lines called fascioles, having a smoother 
appearance than the tubercular surface of the test ; they are fur- 
rows which are strewed with microscopic tubercles destined to 
carry very delicate spines, which, when seen under the micro- 
scope, appear to have the same structure as the Pedicellarie. The 
fascioles have a different disposition in each genus, and afford a 
good character in giving definitions of the same; when the 
fasciole surrounds the ambulacral petals like an undulating 
groove, as in Hemiaster, Schizaster, &c., it is said to be a peri- 
petal ; when it surrounds the single ambulacrum, as in Amphi- 
detus, it is internal ; when it extends along the sides, as in Schi- 
zaster, it is lateral; when it surrounds the circumference of the 
test, as in Pericosmus, it is marginal; when it is limited to the 
base of the anal opening, it is subanal. We find sometimes in 
the same genus more fascioles than one; thus the subanal and 
peripetal are frequently associated together. 
Genus Spatanevs (Klein, 1734). 
Urchins, in general large with a thin test, a convex dorsal sur- 
face, and the antero-lateral and postero-lateral ambulacral areas 
composed of larger: petals than in other Spatangide. The ante- 
