CORALS FROM THE GREAT OOLITE. - AM 
is in part established by the species which, like Z. serialis and I. Lotharinga, form some- 
times a short series of calices where gemmation is very active, and by those Latomeandra 
which are of a massive form. But in all well-preserved fossils belonging to the latter 
genus we have found the common basal plate naked, and presenting simple straight cost, 
whereas in Jsastrea the basal plate is covered with a complete epitheca, and when that 
tunic is worn away the costal striz assume the appearance of radiate fossule. M. 
D’Orbigny has recently formed the genus J/eandrophyllia’ for the species which are in 
some respects intermediate between these two types, having the calices elongated and often 
arranged in short series; but it appears useless to separate generically all the degrees by 
which one form passes to another, and when the principal characters peculiar to one or the 
other of the above-mentioned types become obscure, as in the present case, we prefer 
having recourse to the secondary characters just pointed out, in order to determine the 
genus to which the doubtful species is to be referred. 
Genus CLAUSASTREA.” 
CuausastREA Pratri. Tab. XXII, fig. 5. 
Corallum massive, terminated by a slightly convex surface. Calices large, some- 
what unequal, and not separated by a distinct wall. Colwmella spongiose, well developed. 
Septa of the adjoining corallites quite confluent ; some of them enlarged or much bent at 
their point of junction with the corresponding ones from another individual. They are 
about thirty in each calice; they are rather thin, unequal in size, closely set, and present 
vertical striz on their lateral surfaces: the smaller ones are united to the neighbouring 
large ones by their inner edge. The loculi are closed by well-formed and rather numerous 
dissepiments. The common basal plate is covered with thick granulated costal strize, and 
does not appear to have any epitheca. Diameter of the calices five or six lines. 
We have as yet seen but one ill-preserved specimen of this species ; it was found at 
Comb-Down, near Bath, and belongs to the collection of the Geological Society. It has not 
enabled us to give a complete description of this species, but may easily be distinguished 
from the other two species which remain in the genus Clavsastrea as now circumscribed, 
that is to say characterised, by the absence of walls and columella.* In C. Pratti the 
septa are much thicker than in C. ¢esse/lata* and in C. consobrina.’ 
1 D’Orbigny, Note Sur des Pol. Foss., p. 8. 
2 D’Orbigny, Note Sur des Pol. Fossiles, p. 9, 1849. 
3 See the Introduction to our Memeir on the Palzeoz. Fossil Corals, etc., in the ‘Archives du Museum,’ 
vol. v, p. 107. 
* D’Orbigny, Prod., vol. i, p. 293. 
5 Synastrea consobrina, D'Orbigny, loc. cit. Clausastrea? consobrina, Milne Edwards and Haime, 
loc. cit. 
