INTRODUCTION. xl 
which thus form simple partitions between the visceral cavities, and are thick and compact. 
Calices polygonal; fossula rather deep. Colwmella spongy. Septa slightly exsert, their 
apex arched and denticulated. Well-characterised, denticulated ya/7, corresponding to all 
the septa, except those of the last cyclum. 
Typ. sp., Goniastrea solida, Milne Edw. and J. Haime, Ann., 3™° série, t. x, pl. ix, fig. 7; Madrepora 
solida, var. 6, Forskal, Deser. Anim. in Itin. Orient., p. 131. 
72. Genus APHRASTREA. 
Milne Edw. and J. Haime, Comptes rend., t. xxvu, p. 495, 1848. 
Corallum increasing by fissiparity, and forming a convex mass of a light cellular 
structure, presenting on its under surface a complete, common epitheca. Ca/ices intimately 
united by their margins, which thus assume the appearance of simple partitions. Co/wmella 
spongy. Pali or paliform lobes of the septa corresponding to all the cycla, except the last. 
Septa denticulated, slightly exsert. Dissepiments vesicular, and highly developed. Wadls 
extremely thick, and completely vesicular. 
Typ. sp., Aphrastrea deformis, Milne Edw. and J. Haime, Ann. des Se. Nat., 3™° série, vol. x, tab. ix, 
fig. 11; Astrea deformis, Lamarck, Hist. des An. sans Vert., t. xi, p. 264. 
a 
Ss. 
73. Genus PARASTREA. 
Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 495, 1848. 
Corallum increasing by fissiparity, and having the same general form as in the preceding 
genus, but differing from it by the mode of union of the corallites, which takes place by 
means of the costee and their dissepiments, so that the calices, instead of bemg separated 
only by a common simple margin, have each a distinct margin independent of those 
surrounding it. Sepfa exsert, and armed with teeth, the largest of which are placed near 
the centre of the calice, and often assume the appearance of pali. Dissepiments well 
developed. 
Typ. sp., Parastrea amicorum, Milne Edw. and J. Haime, Ann., 3™ série, vol. x, pl. ix, fig. 9. 
Section V.—ASTREIN A REPTANTES: 
Corallum increasing by the development of buds on stolons, or on membraniform 
basal expansions. ‘The cora/lites not united by their sides, excepting accidentally by 
means of their walls, and remaining short. Sepfa feebly denticulated. Dissepiments 
almost rudimentary. 
74. Genus ANGIA. 
Milne Edw. and J. Haime, Comptes rend., t. xxvu, p. 496, 1848. 
Corallum composed of short, cylindrical corallites, united by a common gemmiferous 
basal expansion, and completely free laterally. Ca/ices sub-circular ; fossula broad and 
