360 MESSRS. H. A.. NICHOLSON AND IJ. ETUEEIDGE 



serA'-ations go, tlie calices certainly do exhibit tooth-like processes 

 extending into the interior of the visceral chamber ; but we have 

 not been able to make out that the number of these is constant, 

 nor are we satisfied that they are identical in their nature with 

 the septal ridge of A. suhorhicularis. 



A. Battershyi, Edw. & H., unquestionably possesses spiniform 

 septa, several of these being placed in general round the circum- 

 ference of a single calice. Not only are these septal spines more 

 numerous than the ridges or teeth of A. suhorhicularis or A. com- 

 pressa, but A. Battershyi seems in all essential respects to be a 

 genuine Favosites,\n.vio\x^ species of the latter genus having distinct 

 though rudimentary septa. 



Various other forms of ^/woZiVes have been stated to possess 

 from one to three septal teeth (such as A. denticulata, Edw. & H., 

 A. repens, Fougt, and A. cryptodens, Billings) ; but we are not suffi- 

 ciently acquainted with these to pronounce any opinion as to their 

 structure. A. septosa, Flem., and A. depressa, Elem., are also pro- 

 vided with structures which have been generally regarded as septal 

 teeth ; but we shall discuss the nature of these subsequently. 



In the meanwhile it is evident that the question as to the validity 

 of the genus Alveolites will turn wholly upon the view which may 

 be taken as to the structure of A. suhorhicularis, Lam., the original 

 type of the genus ; and it seems tolerably certain that with this we 

 may place A. compressa, E. & H., A. LahecJiei, E. & H., and A. 

 Grayi, E. & H., at any I'ate provisionally. "We have seen that the 

 genus Alveolites, as thus typified, agrees with Favosites in the pos- 

 session of corallites with lamellar walls not united by a coenen- 

 chyma, in the existence of mural pores, and in the possession of 

 complete and well-developed tabulae. "We have further seen that 

 the obliquity of the calices, the shortness of the corallites, the 

 size and number of the mural pores, and the fact that the coral- 

 lum is composed of superimposed layers cannot be regarded as 

 points of more than specific value. There remains, then, only to 

 conside]' whether the presence of from one to. three septal ridges 

 (accepting this interpretation of their nature) in the forms just 

 mentioned can be regarded as sufficient to separate them generi- 

 cally from Favosites. "We have satisfied ourselves that no other 

 character can be brought forward which is sufficiently important 

 to elevate Alveolites to the rank of a genus distinct from Favosites ; 

 and this view seems in the main to be precisely that held by Milne- 

 Edwards and Haime. "With our present knowledge it seems unwise 

 to abandon the genus Alveolites altogether ; but it is at the same 



