ECIIINOID GENUS ECHINOCOIÎYS

GENUS ECHINOCORYS IN THE SENONIAN OF BELGIUM 25
occurrence in Belgium but cited it from Limbourg. There it is known from the
Craie of Magas pumilus (equivalent of Nouvelles). The species does occur in
Belgium but not until the time of the Craie de Spiennes and here it is associated
with the variable E. belgicus.
The test of this species is low, with a very low profile (longitudinal) which
slopes more gradually posteriorly, typically abrupt anteriorly but is sometimes
almost symmetrical from the apex in both directions. The base is flat, plastron
prominent, borders angular with a projecting base. The posterior is usually
extended and often carínate and even pointed in some individuals. The peristome
is very slightly subpentagonal in some representatives, but is more often
a broad transverse oval. The periproct is oval to round. When oval is pointed
on the lower end. It is located very near the posterior margin.
Fie. Sa-c. — Echinocorys limburgicus. (a) longitudinal profile (b) contour (c) transverse
prottle of a spécimen from the Craie phosphatic of Ciply at Ciply, flgured spécimen Musée
d'Histoire Naturelle, Brussels.
Although this species varies considerably in some characters, its flat base,
low profile and extended borders are unmistakable and consistent. Its low
upper surface distinguishes it easily from the similar but earlier individuals of
marginatus. The individuals from the Craie de Ciply are very low and represent
more or less the end products of the line and these are associated with others
which are developing toward E. belgicus-\\ke forms as mentioned below.
This species is important because of its connection with the later E. belgicus
and interesting from the viewpoint of its associations with certain other forms.
This form with its varieties exists at certain levels with E. belgicus, E. ciplyensis
and a variety of the latter, arnaudi. The characters of all these forms are often
so intermingled as to cause one almost to give up any attempt to draw line of
distinction. There are many individuals which defy specific identification
except one which is purely arbitrary. E. limburgicus as it occurs in Limbourg
does not show this same association nor intermingling of characters.