R. F. Tomes—On Heterastrea, Lower Lias. 217 
Those of the second cycle are two-thirds the length of the first, 
and those of the third two-thirds the length of those of the second, 
while the septa of the fourth cycle are merely rudimentary. 
Marginal gemmation and fissiparity both occur, but are not frequent. 
This species may be readily distinguished from all the others by 
the small number and the regularity of the septa, the cycles of 
which can readily be determined in a fairly symmetrical calice. In 
the larger and more irregular ones, however, the septa are a little 
more numerous, and the cycles cannot be traced. Another dis- 
tinction consists in the union of the primary septa low down below 
the calice, and thus forming a false columella, which becomes 
conspicuous when the dissepimental floor of the calice has been 
destroyed and the septa worn down. I have not seen this in any 
other species. . 
The most regular calices have a diameter of about two lines, but 
the larger and more irregular ones are nearly three lines in breadth. 
Two examples have been obtained from the Ammonites angulatus 
beds in a field called ‘‘Salmon’s Stile,” near the village of Littleton, 
north-east of Evesham, and another from near the village of 
Cropthorne, west of Evesham. 
HeErerasTR@A BINTONENSIS, Sp. nov. 
There is a large and nearly globular species having a very 
gibbous upper surface, and rather small calices with thick walls, 
which I have at present been unable to refer to any known species. 
It occurs in the Ammonites angulatus beds at Binton Hill, four 
miles west of Stratford-on-Avon, and at Down Hatherley, Gloucester- 
shire, where my friend Mr. Brodie found a specimen, and kindly 
forwarded it to me for my use on the present occasion. Other 
specimens have been taken from the Charlton gravel-pit. 
The calices are rather small, and are mostly hexagonal, but they 
have a rounded appearance, owing to the walls being thickened 
just at the angles. They are very seldom elongated. The septa are 
straight, thin, and in the larger calices there are from forty to forty- 
six. About nine or ten are longer than the others, but do not meet 
in the centre of the calice, there being an open fossula of nearly 
one-fourth of the diameter of the corallite, which is only closed by 
the tabular dissepiments. A corresponding number of septa are 
about half or two-thirds the length of the long ones, and all the 
others are too short and variable to be enumerated. 
Gemmation occurs rather freely, but fissiparity is much less 
common. 
The diameter of a large specimen is about six inches, of a smaller 
one three or four inches. The calices are from two to two and 
a half lines wide. 
The thick walls, the more or less rounded form of the calices, and 
the open fossula will distinguish this species, and I may add that 
all the specimens I have seen have had a more or less globular form. 
HETERASTRHA Sp. 
I have. before me several specimens of a species which is 
