124 BRITISH FOSSIL CORALS. 
Microsolena tuberosa,' M. racemosa,’ M. exeelsa,® and M. incrustata,* differ from it by the 
septa being thicker. and the general form of the corallum being subdendroid. As to 
Microsolena irregularis,’ it appears to be an undeterminable specimen of some Zhamnastrea ; 
nor does the Dactylastrea subramosa® of M. D’Orbigny belong to this genus, being identical 
with our Zhamaastrea. afinis.* 
2. MicrosoLena ExcELsA. Tab. XXV, fig. 5. 
SIDERASTREZA INcCRUSTATA, M*Coy, Ann. and Mag. of Nat. Hist., s. ii, v. li, p. 419, 1848. 
(Not Siderastrea incrustata, Michelin, Icon., 1845.) 
Corallum subdendroid, composed of erect cylindrical digitiform ramified branches. 
Basis covered witha thick, wrinkled, common epitheca, which forms also a few small zones 
at various heights up the branches. The rest of the surface covered with calices, the centre 
of which is occupied by a well-defined but shallow fossula. The corallites are crowded 
together, almost equally developed, and their ca/ices are somewhat polygonal. The columella 
appears to be papillose, but rudimentary. In general, there are about twenty-four septa, and 
consequently three cycla, but sometimes a certain number of the tertiary ones are wanting. 
The septa are confluent, almost equally developed, rather closely set, thin, and bent or 
flexuous outwards. They are composed of distinct ¢radicule, arranged much in the same 
manner as in the preceding species. 
This fine fossil coral forms probably long tufts, but we have seen but fragments of 
about three inches long; the branches are six or seven lines in diameter, and the calices 
about half a line. The specimen here described belongs to Mr. Walton’s collection, and 
was found in the Great Oolite, near Bath. Prof. M‘Coy mentions its having been met with 
in the Great Oolite at Minchinhampton. 
AM. excelsa is very much like J. incrustata,® to which Prof. M‘Coy referred it ; but in 
the latter the epitheca is much more abundant and the calices are shallower. JZ. tuberosa° 
is distinguished by its general form being massive and mammose, but not dendroid, and 
M. ranosa' by the septa being much thicker and less numerous. 
The fossil described by Prof. M‘Coy under the name of Gonropora RACEMOSA” appears 
to differ very little from J/crosolena excelsa ; it was found in the Great Oolite at Min- 
chinhampton, 
1 Alveopora tuberosa, Michelin, Icon., tab. xxix, fig. 7. 
* 
Alveopora racemosa, ibid., tab. xxix, fig. 6. 
Se Dabs acxix, ties Os 
he 
Alveopora incrustuta, Michelin, Icon., tab. xxix, fig. 8. 
> D’Orbigny, Prodr., tab. i, p. 222. 
8 D’Orbigny, Prodr., tab. 11, p. 97. 
Milne Edwards and J. Haime, Ann. Se. Nat., tab. xii, p. 158. 
Michelin, tab. xxix, fig. 8. 9 Tb., tab. xxix, fig. 7. 10 Tb., tab. xxix, fig. 6. 
