xxxvi BRITISH FOSSIL CORALS. 



Section 1L— ASTREINSE CONFLUENTES. 



Corallum massive, increasing by fissiparity, and formed by a series of corallites, the 

 individuality of which is not distinct. The calices, thus united in a common trench, have 

 their septa arranged in a parallel manner in two lines ; and the columella, when existing, 

 is continuous in the whole length of the series. 



These meandriform Corals much resemble the confluent Eusmilinse, and in fossils where 

 the apical teeth of the septa may be worn away, it is often difficult to distinguish them. It 

 may therefore be useful to mention that, in the confluent Astreinse, the gyri are always com- 

 pletely united laterally, and never more or less segregate, which is sometimes the case with 

 the confluent Eusmilinse ; that the columella, which is generally spongy in the latter, never 

 presents that loose structure in this section ; and when it is lamellar, the septa are united to 

 it by an undivided margin in the confluent Eusmilinse, and by a series of trabiculae or 

 processes in the confluent Astreinse ; lastly, that the sides of the septa are more or less 

 granulated in all these Astreinse, and are on the contrary almost glabrous in the meandroid 

 Eusmilinse. 



48. Genus Meandrina. 



(Pars) Lamarck, Hist, des Anim. sans Vert., t. ii, p. 244, 1816 ; Milne Edw. and J. Haime, Comptes rend., 



t. xxvii, p. 493. 



Corallum glomerate, adherent by a very broad basis, and having a very dense 

 structure. Gyri intimately united by their lateral walls, which constitute simple, compact 

 ridges, with a cristate apex. Calicular trenches very long. Columella much developed, 

 spongy and essential (that is to say, not arising from the septa, and distinct from the 

 bottom of the visceral chamber). Septa crowded, enlarging near the columella, and not 

 presenting any appearance of a paliform lobe. Plate or exterior common walls of the 

 corallum covered with a complete delicate epitheca. 



Typ. sp., Meandrina filogra-na, Lamarck, loc. cit., vol. ii, p. 248 ; Michelin, Icon., pi. xi, fig. 7. 



49. Genus Manicina. 



(In parte) Ehrenberg, Corall. des Roth. Meeres, p. 101, 1834; Dana, op. cit., p. 188, 1846; Milne Edw. 

 and J. Haime, Ann. des Sc. Nat., vol. xi, p. 285, 1849. 



Corallum free or sub-pedicellate, in the adult state ; sub-turbinate when young, but 

 becoming convex, and massive. Gyri very long, and united by their walls, so as to 

 form simple ridges, as in the preceding genus ; the apex of the ridge cristate or sulcate. 

 Calicular trench broad and deep. Columella spongy, and even more developed than 

 in Meandrina. Septa thin, crowded, strongly granulated, and armed with delicate, equal 

 teeth ; a well-characterised paliform lobe arising from the edge of the principal septa 

 near the columella. Plate or exterior common wall covered with thin and very delicately- 

 serrated costse ; its inferior part having an incomplete epitheca. 



Typ. sp., Manicina areolata, Ehrenberg, loc. cit. ; Madrepora areolata, Ellis and Solander, op. cit., 

 tab. xlvii, fig. 5. 



