134 
DIASTOPORA. 
Peristomes tall, well raised ; they are somewhat crowded. On 
the upper margin there is a double series of closely packed 
apertures of unequal size on each face of the zoarium. 
Dimensions. 
Distance of apertures in same 
longitudinal series 
Diameter of zooecia ... 
Diameter of apertures 
Fide Pergens. 
3--4omm. 
•25 „ 
B.M., D. 419. 
•18--28 ram. 
I I - ,, 
•05--06 ,, 
Distribution. 
England : 
Middle Chalk : Chatham. 
Foreign : 
Senonian — Maastrichtian : Eoyan, Charente-Inferieure. 
Santonian : Saintes and Bougnaui, Charente-Inferieure. 
Coniacian : Sainte Maure, Tours, Joue, Indre-et-Loire, in 
Craie de Villedieu. 
Turonian: Villedieu, Troot, Souge, Loir-et-Cher ; Rousselirte, near 
Moutier, Charente ; Martigues, Bouches-du-Rhone. 
PiGURE. 
Fig. 8. Part of a zoarium, which is in places hilaminar with 
a zoarial lamina, and elsewhere consists of two separate unilaminar 
sheets ; X 8 dia. Middle Chalk : Chatham. Gamble Coll. D. 419. 
Fig. 8. — Fiastopora auriculark (d’Orh.). Part of a zoarium, partly unilaminar 
and partly hilaminar, with a zoarium layer ; x 8 dia. Middle Chalk : 
Chatham. Gamble Coll. 
Affinities. . 
This ‘ species ’ helps to illustrate the invalidity of the genus 
Mesenteripora and of the zoarial lamina as a generic character. If 
the specimen shown on Fig. 8 were broken, then, according to 
