88 TABULATE CORALS. 



quite circular, and from half to two-thirds of a line in diameter; 

 while the smaller ones are intercalated among the preceding, 

 are often subpolygonal or angular, and vary from a quarter to 

 a third of a line in diameter. Septa represented by radiately 

 arranged spinules, or nearly obsolete. Tabulae numerous, 

 complete, usually curved with their convexity downwards, 

 or flexuous. 



Obs. — The present species was identified by Milne-Edwards 

 and Haime with the Madreporites cristatus of Blumenbach ; and 

 if this identification be correct, it ought to stand as Pachypora 

 cristata, Blum. sp. Lindstrom has, however, expressed the 

 opinion {loc. jam cit), that the form described under the above 

 title by Blumenbach was really the Devonian P. {Favosites) 

 cervicornis, De Blainv., and he therefore revives for the form 

 now under consideration D'Orbigny's name of F. Lonsdalei. 

 Not having it in my power to decide whether or not the iden- 

 tification of Milne-Edwards and Haime is well founded, I have 

 preferred to keep the species in the meanwhile under the name 

 by which all British palaeontologists know it, and by which it is 

 described In the two classical treatises of the French authors. 



Pacliypora cristata, E. and H., usually presents itself in the 

 form of small branching fragments, which may be cylindrical, 

 or which may be so far dilated as to be almost sublobate. I 

 have never seen any fragments even as large as those figured 

 by Edwards and Haime (Brit. Foss. Cor., PI. LXL, figs. 3, 4), 

 and I should imagine the perfect corallum to have attained no 

 great size. The diameter of the branches is most commonly 

 from two to four lines ; and an examination of its internal struc- 

 ture at once shows it to belong to Pachypora, Lindst., and not 

 to Favosites proper. Transverse sections (PI. V., fig. i) show 

 that the corallites are essentially polygonal, and that their pro- 

 per walls are distinctly recognisable ; but the interior of the 

 tubes is narrowed by a dense deposit of sclerenchyma, which 

 increases in quantity as the aperture is approached, and which 

 leaves only a small oval or circular central space. Longitudinal 

 sections (PI. V., figs, i a and i li) show precisely the same fea- 



