ECIIINOID GENUS ECHINOCOIÎYS

GENUS ECHINOCORYS IN THE SENONIAN OF BELGIUM 27
conic variation of belgicus. Closely related to E. limburgicus var. duponti,
both being little removed from the common ancestor, it recalls very closely the
contour of that variety. One variation in the body form of peronicus suggests
a close relationship with the pointed E. belgicus to the extent that the latter may
actually be an intermediate type. This would offer the very strong possibility
that the conic or pointed belgicus was earlier than the average or typical group
of individuals and that it was ancestral to them instead of E. ciplyensis. There
is no stratigraphic or morphological data which exists at present to prove such
a statement, however.
OCCURRENCE : Craie de Nouvelles in Belgium at Heure-le-Romain, but
more commonly known in the Craie of Magus pumilus (Nouvelles) in Limbourg
at Galoppc.
From the Craie phosphatic of Ciply come two forms which are very interesting.
They are both, most certainly, predominated by the characters of pero-
Fic. 10a-6. - Echinocorys limburgicus var. peronicus. (a) longitudinal profile (6) transverse
profile of a specimen from the Craie of Magas pumilus (Nouvelles) at Heure-le-
Romain, figured specimen Musée d'Histoire Naturelle, Brussels (I. G. 4285). Same specimen
figured by Lambert.
nicus. Yet they are mentioned here because they show most distinctly certain
relations to other species. One is very close to the conic E. belgicus and the
other to ciplyensis. The former, and the group of individuals which it represents,
have been explained above. The latter seems to relate to no further
development. And it illustrates a very common occurrence in this genus, where
an unusual or freakish form develops, may be represented by a few individuals
ands seems to pass out of the picture entirely ending in a blind alley so to speak.
Echinocorys belgicus
LAMBERT.
Echinocorys belgicus LAMBERT, 1898, Note sur les Echin. de la Craie de Ciply. (Bull. Soc.
Belg. Geol., n° 11, p. 43, pi. 4, figs. 9-10.)
There are included in this species as it is defined here a group of
forms
which, although remarkably constant in some characters, vary in shape, height