644 
ME. P. MASTIN' DUNCAN ON THE GENERA HETEROPHYLLIA, 
Genus Heterophyllia, M'-Coy. 
Ann. Nat. Hist. 2nd Series, vol. iii. p. 126 ; Brit. Palaeoz. Foss, plate 3 A. figs. 1 & 2. 
1. Heterophyllia ornata, M‘Coy. 
2. grandis , M‘Coy. 
3. mirobilis, sp. nov. 
4. granulata , sp. nov. 
5. angulata , sp. nov. 
6. M‘Coyi, sp. nov. 
7. Lyelli, sp. nov. 
8. SedgwicJci , sp. nov. 
The new species come from highly fossiliferous beds which are very low down in the 
Carboniferous series. 
The generic diagnosis of M‘Coy is as follows ; and it is proposed to modify it slightly 
after the description of the new species. 
Gen. Char. — “ Stem elongate, subcylindrical, irregularly fluted longitudinally ; hori- 
zontal section , few distinct lamellae, destitute of any order of arrangement, but irregu- 
larly branching and coalescing in their passage from the solid external walls towards 
some indefinite point near the centre where the few main lamellae irregularly anasto- 
mose ; vertical section , showing about the middle an irregularly flexuous line (the edge of 
one or two of the radiating vertical lamellae), from which on each side a row of thin, 
distant, sigmoidally curved plates extends obliquely upwards and outwards, forming a 
row of large rhomboidal cells on each side.” 
According to the terminology now used, the stem is the corallum, the flutings are 
intercostal spaces, the lamellae are septa, and the curved and oblique plates are endo- 
thecal dissepiments. 
Description of the Species. 
1. Hetekophyllia grandis*, M‘Coy. 
The corallum is tall and slightly flexuous. The costae are few in number, and pro- 
ject as large polygonal unequal ridges. The intercostal spaces are grooves, and are 
deep as well as unequal. The horizontal section has an irregularly angular outline. 
The surface of the corallum is smooth. The septa are very irregular in disposition and 
number. The diameter of the stem is five lines. 
The species is an uncommon form in the Mountain-limestone of Derbyshire. 
2. Heterophyllia ornata, M‘Coy. 
The corallum is subcylindrical, long, and flexuous. The costae are narrow, subequal, 
and are ornamented with small and rounded tubercles. The costae are about sixteen in 
number. The intercostal spaces are flat, and are rather wider than the costae. The 
* These descriptions of M‘Cor’s species are altered so as to meet the requirements of the terminology of the 
received classification. 
