INTRODUCTION. hx 
4. Genus FistULIPORA. 
M’Coy, Ann. and Mag. of Nat. Hist., 2d series, vol. iii, p. 130, 1849. 
Corallum with vesicular ccenenchyma ; thick walls and infundibuliform tabule. 
Typ. sp., Fistulipora minor, M’Coy, loc. cit., figs. a, b. 
5. Genus PLASMOPORA. 
Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 262, 1849. 
Corallum free, sub-hemispheric, with a basal plate covered with an epitheca presenting 
concentric folds. Cal/ices immersed. Sepfa rudimentary. Zabule horizontal. Walls 
thin. Canenchyma composed of large, vertical, radiate lamin, united by smaller hori- 
zontal plates, and resembling much the costal ccenenchyma of the Astreidee. 
Typ. sp., Plasmopora petaliformis, nob.; Porites petaliformis, Lonsdale, in Murchison, Sil. Syst., 
pl. xvi, fig. 4. 
6. Genus PRropora. 
Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 262, 1849. 
Corallum differmg from the preceding genus by the calices having exsert margins ; the 
septa being more developed, and extending outwards so as to constitute small coste. 
Typ. sp., Propora tubulata, nob. ; Porites tubulata, Lonsdale, Sil. Syst., pl. xvi, figs. 3, 3°, 3° (ceteris 
exclusis). 
7. Genus AXOPORA. 
Corallum composite, incrusting, and forming thin expansions, which are often super- 
posed. Canenchyma abundant, and forming irregular ridges between the calices, which 
are small and deep. Septa rudimentary. Colwmella well developed, fasciculate, and 
expanding at its passage through each of the tabule. 
Typ. sp., dxopora pyriformis, nob. ; Geodia pyriformis, Michelin, Icon., tab. xlvi, fig. 2. 
8. Genus LOBOPORA. 
Corallum having the same structure as in the preceding genus, but forming large, 
thick, foliaceous expansions, the two surfaces of which are covered with calices. 
Typ. sp., Lobopora Solanderi, nob. ; Palmipora Solanderi, Michelin, op. cit., tab. xlv, fig. 9. 
