CKISINA. 
181 
Diagnosis. 
Zoarium dicliotoniously branched : the branches anastomose 
occasionally ; but the zoarium nsnally remains loose and 
open, and rarely occurs as a definite regular network. The 
branches taper rapidl}" towards theii' extremities. On the 
reverse edge there are often some irregularly distributed 
zooecia with prominent peristomes. 
Zooecia small. The number of apertures in a vertical series is 
small, ranging from five to seven. The series are iiTegular 
and broken. 
Dimensions. 
Diameter of branch . . . 
Diameter of zooecia ... 
Diameter ot aperture ... 
Distance of peristomial 
series 
Fide Per gens. 
*14 mm. 
•06 „ 
B.M., D. 3965. 
•5-'7 mm. 
• 1--12 
> 1 
•35--6 ,, 
Distkibution. 
England : 
Upper Chalk : Bromley, Kent. 
Middle Chalk ; Chatliam ; Freshwater, Isle of Wight (? zone of 
Holaster planus). 
Foreign : 
Senonian — Maastrichtian : Meudon ; Fecamp, Seine - Inferieure ; 
Chateaudun, Eure-et-Loir. 
Campanian : Eiigen. 
Santonian: L’ Arche de Leves. 
Figures. 
PI. IX. Fig. 1. A forked branch of a zoarium. Fig. \a, the 
obverse edge, X 10 dia. ; Fig. iJ, side view, X 10 dia. ; Fig. It?, 
the reverse edge, X 10 dia. Middle Chalk: Chatham. Gamble 
Coll. D. 3965. 
PI. IX. Fig. 2. The reverse edge of a specimen of var. com- 
planata] X 12 dia. Middle Chalk: Chatham. Gamble Coll. 
D. 385. 
PI. IX. Fig. 3. A young zoarium, X 2 dia. Chalk: Freshwater, 
I. of Wight. I. S. Gardner Coll. B. 70. 
Aepinities. 
This species is marked bj" the looseness of the zoarium and 
the small number of apertures in the vertical series. The adult 
