INTRODUCTION. xliii 



which thus form simple partitions between the visceral cavities, and are thick and compact. 

 Calices polygonal ; fossula rather deep. Columella spongy. Septa slightly exsert, their 

 apex arched and denticulated. Well-characterised, denticulated pali, corresponding to all 

 the septa, except those of the last cyclum. 



Typ. sp., Goniastrea solida, Milne Edw. and J. Haime, Ann., 3 me serie, t. x, pi. ix, fig. 7 ; Madreporu 

 solida, var. b, Forskal, Descr. Anim. in Itin. Orient., p. 131. 



72. Genus Aphrastrea. 



Milne Edw. and J. Haime, Comptes rend., t. xxvii, 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 Calices intimately 

 united by their margins, which thus assume the appearance of simple partitions. Columella 

 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. Walls 

 extremely thick, and completely vesicular. 



Typ. sp., Aphrastrea deformis, Milne Edw. and J. Haime, Ann. des Sc. Nat., 3 me serie, vol. x, tab. ix, 

 fig. 11 ; Astrea deformis, Lamarck, Hist, des An. sans Vert., t. xi, p. 264. 



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 costse and their dissepiments, so that the calices, instead of being separated 

 only by a common simple margin, have each a distinct margin independent of those 

 surrounding it. Septa 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 me serie, vol. x, pi. ix, fig. 9. 



Section V.— ASTREINtE REPTANTES. 



Corallum increasing by the development of buds on stolons, or on membraniform 

 basal expansions. The corallites not united by their sides, excepting accidentally by 

 means of their walls, and remaining short. Septa feebly denticulated. Dissepiments 

 almost rudimentary. 



74. Genus Angia. 



Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 496, 184S. 



Corallum composed of short, cylindrical corallites, united by a common gemmiferous 

 basal expansion, and completely free laterally. Calices sub-circular ; fossula broad and 



