402 
ATAGMA. 
Diagnosis. 
Zoarium large ; the branches are long, di'V'iding at distant 
intervals, and irregularly. The surface is uneven and nodular. 
There is a small axial bundle surrounded by one or more 
lamellae. At the distal ends the apertures are uniformly 
scattered, hut in the basal portions they occur in groups 
round smooth, nodular prominences. 
Maculae in single circles round the apertures. 
Apertures often with a straight lower edge. 
Dimensions. 
Height of zoarium ... 
Diameter of branches 
Diameter of aperture 
Diameter of zooecia ... 
Distribution. 
Lower Chalk : Sussex. 
110 mm. 
3-5 ,, 
•12--15 „ 
•2o-*3 ,, 
LIST OF SPECIMENS. 
30,864. A large branched zoarium. Lower Chalk. Sussex. Dixon Coll. 
Figd. Lonsdale, G-eol. Suss. pi. xviii. b, fig. 6. 
B. 4472, B. 4473, B. 4474, B. 4475, B. 4476. Five fragments from the Lower 
Chalk, Sussex. Figured by Lonsdale, op. eit. pi. xviii. b, figs. ^a-g. 
2. Atagma papularia (Michelin), 1843. 
Synonymy. 
Ceriopora papularia^ Michelin, 1843-5. Icon. Zooph. pp. 124, 206, pi. xxxii. 
fig. 7. 
,, ,, d’Orbigny, 1850. Prod. Pal. vol. ii. p.'184. 
,, ,, Winkler, 1864. Mus. Teyl. : Cat. Pal. livr. ii. p. 210. 
non Reptomultidausa papularia, d’Orbigny, 1853-4. Bry. Cret. p. 901, pi. 767, 
figs. 11-14. 
Bitaxia {Reptomulticlausa) papularia, Pergens, 1890. Revision, p. 337. 
Diagnosis. 
Zoarium of stout branches, which anastomose repeatedly. The 
surface is nodular. 
Apertures circular ; irregularly distributed close or distant, 
separated by wide cancellous areas or by a single circle of 
maculse. 
