SEMICYTIS. 
119 
adopted in this Catalogue, are both species of Hommsolen. They 
do not belong to the Cancellata. Their exclusion leaves Semicytis 
as a natural group, which is closely related to Desmepora. Bucaille, 
indeed, reduces Semicytis to a mere synonym of Desmepora. The 
two genera may, however, be retained owing to the absence 
from Desmepora of the ridge on the obverse surface. The affinities 
of the two genera are unquestionably close, and, should they he 
united, Desmepora has priority. 
Semicytis rugosa (d’Orbigny), 1850. 
Synonymy. 
Osciilipora rugosa, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 268. 
Semicytis ,, d’Orbigny, 1854. Bry. Cret. p. 1049, pi. 795, figs. 1-7. 
Desmeopora ,, Bucaille, 1890. Bry. Cret. Seine-Inf. : Bull. Soc. Sci. nat. 
Rouen, vol. xxv. p. 512. 
Diagnosis. 
Zoarium with a long, narrow, vertical peduncle rising from 
a group of branches, which are infundibuliform in arrange- 
ment, rising from a long cylindrical stem. 
Keverse surface covered with pores placed serially between 
irregularly curved, reticular ribs, of which the longitudinal 
members of the series are curved. 
Lateral processes short and thick, rising from the anterior 
part of the side of the branches and projecting forward. 
Apertures occurring between longitudinal ribs on the reverse 
surface and extending over the pinnules. 
Dimensions. 
Diameter of branch 
Diameter of lateral processes . . . 
Length of lateral processes 
Average distance of lateral processes 
Diameter of zooecia 
Diameter of apertures 
B.M. 
D. 3966. 
•6-*8 mm. 
•3-*4 „ 
•5-1 „ 
•8 „ 
•13--15 ,, 
•08 ,, 
Distribution. 
British : 
Middle Chalk — Zone of Micraster cortestudinarium : Chatham ; near 
Folkestone [fide d’Orbigny). 
Foreign : 
Senonian — Coniacian : Fecamp, Seine-Inferieure. 
Senonian ; Carancy, Pas-de-Calais. 
