IDMONEA. 
lol 
Diagnosis. 
Zoarium encrusting, compound ; composed of a number of 
iiTcgularlv radial ridges, connected by a lateral basal 
expansion. The ridges are simple, and do not branch. 
Xevr ridges rise independently from the basal expansion. 
Apertures confined to the ridges. In vertical or slightly oblique 
rows. The rows are crowded, and those on the two sides of 
the ridge are alternate. Peristomes only slightly raised. 
Dimensions. 
"Width of zoarial ridge 
Height of zoarial ridge 
Diameter of aperture 
Distance of peristomial series ... 
Disteibution. 
Lower Greensand ; Farringdon. 
Figuees. 
PI. YIII. Fig. \a. Part of a large encrusting zoarium, shoA\ung 
three ridges and basal selvage ; X 5 dia. Fig. 1^, a zoarial ridge 
from the same, seen from the side ; x 5 dia. Lower Greensand : 
Farringdon. Cunnington Coll. 55,110. 
Xo. 55,110. 
1-1*4 mm. 
1-4 „ 
• 1--2 „ 
•6 „ 
Affinities. 
This Bryozoan is an ally of Idmonea triquetra, Lam., the type of 
the genus. Its nearest Cretaceous ally is Idmonea alipea, fr*om 
which it differs by the smaller number of apertures in the transverse 
rows. It differs from the true LoqjJioUpis of von Hagenow, which 
is a fasciculate form. This species is intennediate between the 
type species and those on which d’Orbigny has founded Beptoclausa. 
LIST OF spect:\iex's. 
55,110. A large zoarium encrusting a chert pebble. Lower Greensand. 
Farringdon. Cunnington Coll. Figd. PI. YIII. Fig. 1. 
51,164. A zoarium encrusting cast of a lamelhbranch, and three slides 
th oaring longitudinal, transverse, and horizontal sections. Lower 
Greensand. Farringdon. Purchased of J. Shaip, Esq. 
D. 4503. Five zoaria on chert pebbles. Lower Greensand. Farringdon. 
Cunnington Coll. 
