304 MR. W. D. LANG ON GROWTH-STAGES [ Mar. 2, 
distinguished and specimens B.M. nos. R. 13889 and R. 6614, 
from the Norwich Chalk, are here described. Probably these 
two are the proximal and distal parts of one corallum; but as 
they do not exactly fit together, it is not safe to assume that 
they are one specimen, and the former is chosen as typical of 
the species, because it shows the early as wellas the adult growth- 
stages. 
The cost are low when they first appear, with few, large granules 
tending to mass (text-fig. 45 A’, costal-stage VII.), but soon 
become thinner with a crest of massed granules (text-fig. 45, b’, 
costal-stage VIIT.). The first rejuvenescence occurs very early in 
the corallum and throws the coste back to stage VII. (text- 
fig. 45, A*), whence they rapidly pass to stage VIII. (text- 
fig. 45, B*), and again rapidly to stage IX. (text-fig. 45, C’) which 
is characterised by high, thin, wavy coste with no granules and 
with occasional intercostal dissepiments; the latter form an 
irregular ring round the corallum at the second rejuvenescence, 
which takes place low down in the Trochoid shape-stage. The 
costal history need be described in detail no further, as there is 
henceforth only a frequent alternation of costal-stages VIII. and 
IX., the latter being predominant and the former tending to 
disappear altogether in the Cylindrical shape-stage (text- 
fig. 45, 1B Cay: 
8. PARASMILIA MONILIS Duncan. (Text-fig. 46.) 
Parasmilia monilis Dunean, 1869, ‘“ British Fossil Corals,” 
Mon. Pal. Soe. p. 12, pl. v. figs. 4, 5, 6. 
B.M. no. R. 6477. 
The determination of this species cannot be regarded as settled 
until the Type-specimen comes to light and has been examined, or 
its loss certified and a new Type chosen. It is not easy from 
Duncan’s figure to see if intercostal dissepiments are present ; 
they certainly do not appear in enlarged figured pieces of coste 
high on the corallum; on the peduncle, of which there is also an 
enlarged drawing, they would not be expected. 
A form represented by the B.M. specimen No. R. 6477 from 
the zone of Belemnitella mucronata Schlotheim, of East Harnham, 
Salisbury, from the Tomes Collection, is here described as P. monilis, 
as it closely resembles Duncan’s figure. Small but numerous inter- 
costal dissepiments are present in the distal part of the corallum, 
and it is chiefly the presence of these that makes the determination 
doubtful. Tomes’ specimen is one of a series described by him as 
P. mantelli Edwards & Haime. There is also a specimen of 
P. monilis as here defined, B.M. no. R. 6618, figured in 1850 by 
Lonsdale in Dixon’s ‘Geology of Sussex,’ pl. xviii. fig. 9, as 
Monocarya centralis (Mantell). This, however, has not been 
chosen for description as the whole of the proximal end is gone, 
and its exact horizon and locality are unknown. 
P. monilis as here determined is remarkable for showing an 
