BICAVE A. 
105 
The body of the zoarium is discoid, or wheel- shaped, and has 
on the margin a series of vertical radial projections as in a cog- 
wheel. The cogs usually project for a distance nearly equal 
to the radius of the disc. The cogs may be prolonged at their 
upper, outer comer into spike-like fasciculi. The upper surface 
between the bases of the fasciculi is depressed, and occupied 
by the small, crowded, irregular apertures of the intermediate, 
subordinate zocecia. 
Stems appear solid and imperforate, as they are covered by 
a lamina, which is fluted vertically or wrinkled horizontally. 
Two zoaiia may arise from one stem, or several zoaria may 
arise from a stolon. 
Dimensions. 
B.M. D. 2297. 
B.M. D.2296. 
mm. 
mm. 
Diameter of body across central disc 
3 
3-5-3-75 
Diameter of body, including projections 
5 
6-7 
Length of stem 
2 
— 
Diameter of stem 
•8-1 
1 
Zocecia: diameter 
— 
•15--17 
, , diameter of aperture ... 
•08 
•08--1 
Number of fasciculi 
— 
8-9 
Disteibution.’ 
Lower Chalk (Turonian) — near base of the Holaster planus zone: Isle of 
'Wight, at Freshwater, on the Military Road ; Compton Bay ; Culver 
Cliff; Shalcomhe Down (Pit No. L3) ; Arreton Down (Pit Nos. 19 
and 20) ; Brading Down (Pit. No. 37) ; Cansbrooke (Pit No. 51). 
Mupe Bay, Dorset. 
Figuees. 
PL II. Fig. 4. The upper surface of a zoarium ; X 8 dia. 
Chalk : near Freshwater, Isle of Wight. Capron Coll. D. 2996. 
PI. II. Fig. 5. The lower side of another zoarium ; X 7 dia. 
Chalk : near Freshwater, Isle of Wight. Capron Coll. D. 2996. 
PL II. Fig. 6. Two zoaria joined by a common stem ; X 6 dia. 
Chalk. Loc. unknown. Old Coll. D. 2997. 
Affinities. 
This species is very well marked. It has long been well known 
to collectors from the Isle of Wight, and has been described as the 
From information kindly supplied by Dr. A. W. Rowe. 
