170 
CEISIXA. 
Foreign : 
Senonian — Maastriclitian : Maastricht ; Meudon ; Fecamp, Seine- 
Inferieure ; Sainte-Colombe, Manche ; Ciply ; Chapet, 
Seine-et-Oise. 
Campanian : Eiigen. 
Coniacian : Joue, Indre-et-Loire ; Yendome, Loir-et-Cher. 
Figures. 
PL IX. Fig. 4. A small, simple zoarium, of the depressa\ 2 iV\Qi\, 
X 12 dia. Middle Chalk : Chatham. Gamble Coil. D. 526. 
PI. IX. Fig. 5. Part of a branched zoarium, with worn peri- 
stomes ; X 18 dia. Fpper Chalk: Gravesend. Tine Coll. D. 968. 
PI. XI. Fig. 11. Side view of a regular branch with low 
peristomes, small zooecia, and a gonoeciiim ; X 10 dia. Middle 
Chalk : Chatham. Gamble Coll. D. 4068. 
Affinities. 
Owing to the presence of a median irregular series of zooecia, this 
‘ species ’ belongs to the group for which Jullien has proposed the 
genus Ter via. 
Idmonea suhgracilis is intermediate between I. unipora and 
I. dorsata : it resembles the former by its thin branches, but differs 
by the constantly biserial apertures, the median series of zooecia, 
and the greater prominence of the peristomes. 
Pergens includes Clavituhigera depressa as a synonym ; it repre- 
sents a clavate branch. 
Marsson’s Filisparsa pulcliella appears to be the delicate, distal 
ends of branches of this species. Typical specimens of C. suh- 
gracilis have sometimes only uniserial apertures and low peristomes. 
The specimens in the Museum collection numbered D. 1000 and 
D. 4499 are indistinguishable from typical C. suhgracilis and yet 
appear identical with Marsson’s figure. The pulcliella variety may 
be a deeper-water form than those from Touraine. 
LIST OF SPECIMENS. 
British. 
D. 526. A smaU simple zoarium approaching the Clavituhigera deprensa 
variety. Middle Chalk. Chatham. Gamble Coll. Figd. 
PI. IX. Fig. 4. 
D. 968. Seven fragments (on slide). Upper Chalk. Gravesend. Yine-Coll. 
The peristomes are worn down. Figd. PI. IX. Fig. 5. 
D. 4068. A branch with gonoecium (on shde), with Spiropora cretacea (Orb.). 
Middle Chalk. Chatham. Gamble Coll. Figd. PL XI. Fig. 11. 
