INTRODUCTION. xxxvii 



50. Genus Diploma. 



Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 493, 1848. 



Corallum glomerate, adherent by a broad basis, and of a dense structure. Gyri long, 

 very sinuous, and united by highly-developed costae, and not by the walls themselves ; 

 ridges complex, presenting on each side a mural crest, and in the middle a broad concave 

 groove or ambulacrum, formed by the costae and their dissepiments. Columella spongy, 

 essential, and well developed. Septa strong, exsert, and armed with closely-set teeth, 

 the largest of which are near the walls. 



Typ. sp., Diploria cerebriformis, Milne Edw. and J. Haime, Ann., t. xi, p. 289 ; Meandrina cerebriformis, 

 Lamarck, op. cit., vol. ii, p. 246 ; Seba Tb.es., vol. iii, tab. cxii, No. 6. 



51. Genus Leptoria. 



Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 493, 1848. 



Corallum glomerate, of a light spongy structure. Gyri very long, and limited by 

 their walls, which are thin or cellulose, and form simple intercalicular ridges. Columella 

 lamellar ; its upper edge projecting slightly, and regularly lobated. Septa united to the 

 columella by means of marginal trabiculae ; their upper edge slightly exsert, and armed 

 with very small irregular teeth. Plate covered with a thin but complete common epitheca. 



Typ. sp., Leptoria tenuis, Milne Edw. and Haime, Ann. des Sc. Nat., 3 me ser., vol. x, tab. viii, fig. 11 ; 

 Meandrina cerebriformis, Quoy and Gaimard, Voy. de l'Astrol., Zoopb., pi. xviii, figs. 2, 3 ; Meandrina tenuis, 

 Dana, op. cit., p. 262 ; Milne Edw., Atlas du Regne An. de Cuvier, Zoopb., pi. lxxxiv ter, fig. 2. 



52. Genus Cceloria. 



Mdne Edw. and J. Haime, Comptes rend., t. xxvii, p. 493, 1848. 



Corallum resembling much the true Meandrina, but differing from the four preceding 

 genera by its rudimentary columella, which is not essential, but septal, and formed by 

 trabiculae, springing from the margin of the septa. Gyri long, and united by their walls, 

 the tissue of which is cellular ; ridges simple and continuous. Septa delicate, and having 

 neither a paliform lobe nor a lateral expansion near the columella. 



Typ. sp., Cceloria labyrinthica, Milne Edw. and J. Haime, Ann. des Sc. Nat., 3 mc serie, t. xi, p. 194 ; 

 Madrepora labyrinthica, Ellis and Solander, op. cit., tab. xlvi, figs. 3, 4. 



53. Genus Astroria. 



Milne Edw. and J. Haime, Comptes rend., t. xxvii, p. 493, 1848. 



Corallum having the same structure as in the preceding genus, but formed of very short 

 gyri, the corallites tending to individualization. This form is intermediate between the 

 ordinary confluent Astreidae (or Meandrinae) and the agglomerated Astreidae, such as true 

 Astrea. 



Typ. sp., Astroria dcedalea, Milne Edw. and J. Haime, Ann. des Sc. Nat., t. xi, p. 297 ; Madrepora 

 diedalea, Ellis and Solander, op. cit., tab. xlvi, figs. 1, 2. 



