THOLOPORA. 
281 
radial lines of apertures of Tholopora, and that there is a distinct 
species having the same habit, but with the apertures irregularly 
arranged. The latter is a true Multicrescis ; such a form from the 
Haldon Hills is represented on PI. Y. Pig. 6. 
The Trepostomatous structure of the zoarium is well shown in 
the sections figured by i^ovak {op. cit. pi. ix. figs. 19, 20). 
LIST OF SPECIMENS. 
D. 4441, Three zoaria. Six apertures in the vertical series. Cenomanian — 
Korycaner Schichten. Kamajk, Bohemia. Purchased of Dr. Anton 
Fric. 
D. 4440. Three zoaria. Cenomanian — Korycaner Schichten. Zhislav, Bohemia. 
Purchased of Dr. Anton Fric. 
7. Tholopora cantiana (Gregory), 1909. 
Synonymy. 
Multicrescis variabilis, non d’Orb., Gamble, 1896. Cat. Bry. Chatham, p. 4. 
Bomopora cantiana, Gregor)^ 1909. New Cret. Bry. ; Geol. Mag. dec. v. vol. vi. 
p. 66. 
Diagnosis. 
Zoarium small, of stems which are circular in section and 
marked by numerous horizontal annular constrictions. 
The upper segments gradually decrease in diameter, and the 
zoarium ends in a blunt point. 
Apertures in short vertical series, including from two to six 
apertures in a series. 
Mesopores scanty. 
Dimensions. 
D. 2849. D. 2759. 
mm. mm. 
Height of zoarium ... ... more than 5 . . . 4 
Maximum diameter of zoarium .. 2*4 ... 2*2 
Diameter of apertures ‘15--20 ... •15-*20 
Distribution. 
Upper Chalk — Zone of Micraster coranguinum : Bromley, Kent. 
Middle Chalk — Zone of Micraster cortestudmarium : Chatham. 
Figures. 
PI. YIII. Fig. 2. A zoarium from the side ; X 5 dia. Upper 
Chalk : Bromley. J. Simmons Coll. D. 2849. 
PI. VIII. Fig. 3. The type-specimen from the side ; X 5 dia. 
Middle Chalk — Zone of Micraster cortestudinarium : Chatham. Vine 
Coll. D. 2759. 
