CORALS FROM THE MOUNTAIN LIMESTONE. 199 
DipHYPHYLLUM PAUCIRADIALE, D’ Orbigny, Prod. de Palont., vol. i, p. 159, 1850. 
DIPHYPHYLLUM IRREGULARE, D’ Orbigny, Prod. de Paléont., vol. i, p. 159, 1850. 
LITHOSTROTION IRREGULARE, Milne Edwards and Jules Haime, Polyp. Foss. des Terr. 
Paleeoz., p. 436, 1851. 
LITHOSTROTION PAUCIRADIALE, Milne Edwards and Jules Haime, ibid., p. 439. 
SIPHONODENDRON AGGREGATUM, M‘Coy, Brit. Paleeoz. Foss., p. 108, 1851. 
Corallum fasciculate. Corallites very tall, cylindrical, and flexuous, especially towards 
their basis, where they are proliferous, and many of their young branches seem to have 
avorted, and to have become cemented to the neighbourmg individuals. Colwmel/a but 
slightly compressed. Septa extremely thin, and rather widely set; the principal ones 
(18 in the young corallites, and 24 in the adult,) extending almost to the centre of the 
Corallite ; the intermediate ones coming very near to the principal ones near the Colwmel/a, 
and the small ones almost rudimentary. Zasule placed at about a quarter of a line apart, 
and presenting only a very small smooth portion. Diameter of the calices about 23 lines ; 
that of the smooth part of the tabulz not quite 1 line. 
Found at Castleton, Corwen, and Oswestry ; according to Professor Phillips, at Bristol, 
Ashfell, and in Northumberland; according to Col. Portlock, at Martindesert, Desert- 
creat; and, according to Professor M‘Coy, Magheramore and Tobercury. It is also met 
with in the Oural mountains. 
Specimens are in the collections of the Museum of Practical Geology, Professor 
Phillips, Mr. Bowerbank, the Paris Museum, &c. 
In this species the corallites are broader and more lamelliferous than in LZ. junceum,! 
and on the contrary, smaller and not provided with as many septa as in LZ. affine,? 
L. Martini and L. Phillipsi* It is more difficult to distinguish Z. irregulare from 
L. antiquum,’ L. harmodites,’ and L. Stokesi.” The latter differs from it by the existence 
of mural expansions, which are never met with in the above-described species, and 
L. harmodites differs from it by the existence of connecting tubes, which resemble those 
of Syringopora. L. antiquum is most closely allied to it, but its septa are less numerous, 
although the diameter of the calice be somewhat larger, and its columella is stouter and 
more compressed. 
We are inclined to think that the Diphyphyllum gracile of Professor M‘Coy ® is a spe- 
cimen of Lithostrotion irregulare, in which the Columella has been accidentally destroyed 
by the process of fossilisation. This Coral was found at Lowick in Northumberland. 
1 See tab. xli, fig. 1. 2 See tab. xxxix, fig. 2. 3 See tab. xl, fig. 2. 
* See tab. xxxix, fig. 3. 
5 Milne Edwards and J. Haime, Polyp. Paleeoz., p. 439; Lithodendron cespitosum, Goldfuss, Petref. 
Germ., tab. xiii, fig. 4. 
6 Milne Edwards and J. Haime, op. cit., tab. xx, fig. 2. 
7 Milne Edwards and Jules Haime, op. cit., tab. xv, fig. 1. 
8 Ann, and Mag. of Nat. Hist., vol. iii, p. 2; vol. vii, p. 168; and Brit. Palzeoz. Foss., p. 88, figs. d, e, 7. 
