120 TABULATE CORALS. 



redefine Alveolites as follows : " Corallum forming a convex 

 or dendroid mass. Calices oblique, subtriangular, or semi- 

 circular, presenting interiorly a longitudinal protuberance which 

 is opposed to two other smaller protuberances. These emi- 

 nences appear to represent the primary septa, and no other 

 traces of the septal apparatus can be detected. The walls are 

 simple, well developed, pierced with a small number of mural 

 pores. The tabulae are complete and horizontal." After 

 giving a history of the genus, the authors just quoted remark 

 that the elongated teeth or eminences above alluded to consti- 

 tute the most remarkable feature of the genus Alveolites, and 

 that they are to be regarded as so many primary septa, the 

 other three which form the normal cycle of six being aborted. 

 They further add that one of these three septal teeth is always 

 more pronounced than the other two, and that these latter may 

 be wholly wanting. 



In the ' Histoire Naturelle des Coralliaires ' (vol. iii. p. 263, 

 i860), Milne - Edwards makes the following remarks as to 

 Alveolites : "The most striking c\i-&x2.QX^r oi Alveolites is fur- 

 nished by the septal system, which is represented by three teeth 

 or vertical projections — one situated on the inside face of the 

 outer lip of the calice, the others opposite the preceding, upon 

 the inner lip of the corallite, and sometimes rudimentary. The 

 calices are oblique, subtriangular, or subhemispherical. Walls 

 simple, well developed, and pierced by a small number of 

 pores. Tabulae complete and horizontal. . . . The elon- 

 gated teeth or vertical projections which we see in the interior 

 of the visceral chambers of the corallites _/(7r;;z the most peculiar 

 charaeter of Alveolites, and recall the three principal septa 

 which characterise the genus Heteroccenia amongst the As- 

 traeidae. . . . It is also worthy of note that one of the septal 

 projections is more developed than the other two, and often it 

 alone may exist." 



In briefly analysing the above, it will be obvious. In the first 

 place, that Lamarck's definition of the genus Alveolites does 

 not contain a single character which would at the present day 



