CORALS FROM THE MOUNTAIN LIMESTONE. 195 
5. Lirgostrotion M‘Coyanum. ‘Tab. XLII, figs. 2, 2a, 26. 
Lirnostrotrion M‘Coyanum, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Paloz., 
p- 444, 18951. 
This fossil much resembles Z. Portlocki, but the corallites are smaller and much more 
unequally developed; its inner walls are more distinct, and the septa less numerous, 
(20 or 24,) somewhat thicker, and less unequal in size alternately ; they form a prominent 
circle round the columella, which is also prominent. Diagonal of the large individuals 
13 line, rarely 2 lines. 
Found at Oswestry and Matlock, Derbyshire. Specimens are in the collection of the 
Museum of Practical Geology, of Mr. Bowerbank, and of the Paris Museum. 
6. LirHosrrotion (?) CONCINNUM. 
DIpHYPHYLLUM CONCINNUM, Lonsdale, in Murch., Vern., Keys., Russ. and Ural, vol. i, p. 624, 
pl. a, fig. 4, 1845. 
— LATIsEPTATUM, M‘Coy, Ann. and Mag. of Nat. Hist., 2d ser., vol. iui, p. 8, 
1849. 
Lirnostrotron (?) concinnum, Milne Edwards and Jules Haime, Pol. Foss. des Terr. 
Paleoz., p. 446, 1851. 
DIPHYPHYLLUM LATESEPTATUM, M‘Coy, Brit. Paleeoz. Foss., p. 88, pl. ili, fig. 10, 1851. 
Corallites elongate, cylindrical, presenting slight circular growth swellings, and 
surrounded with a thin epitheca. Inner wad/s rather distinct. Principal septa 32 in 
number, very thin, and alternating with an equal number of small ones. Zabule well 
developed, smooth towards the centre, the exterior zone occupied by oblique, slightly 
vesicular dissepiments. Diameter from 3 to 5 lines. 
Found at Corwen and in the Oural Mountains. Specimens are in the collection of the 
Cambridge Museum, and of M. de Verneuil. 
All the fossils of this species that we have examined were in a bad state of preservation, 
and the genus Diphyphyllum, established for them by Mr. Lonsdale, does not appear to us 
sufficiently characterised, for it differs from Lithostrotion only by the absence of the 
columella, and we have much reason to think that the non-existence of that organ is here 
merely accidental, and due to the process of fossilisation. The considerations which induced 
Mr. Lonsdale to form this new generic division were founded on the supposed fissiparous 
mode of multiplication of these corals; but after close examination of their structure we 
are fully convinced that they are not in reality fissiparous, and that the appearance, which 
at first sight may be taken for a fissiparous division of the calice, is due to the rapid 
lateral coalescence of the young individual produced by gemmiparity and the parent 
corallite. 
26 
