GENERA OF CH^ETETID^E AND MONTICULIPORIDsE. 281 



lae." The "monticules" or "mamelons" are circumscribed 

 areas on the surface of the corallum, which are, typically, ele- 

 vated so as to form a series of rounded, oval, or elongated 



Fig. 38. A, Vertical section of a few of the corallites of Stenopora Tasmaniensis, Lonsd., in 

 the final portion of their course, enlarged twenty times, showing the annular thickenings 

 of the tubes and the remote tabulae ; B, Tangential section of the same, taken just below 

 the surface, similarly enlarged, showing the transversely divided spiniform corallites be- 

 tween the ordinary tubes. Carboniferous, Australia. 



projections, but which may be nearly or quite level with the 

 general surface. Sometimes the " monticules " are composed 

 of corallites which differ in no conspicuous feature from those 

 which form the rest of the coral (e.g., in M. ramosa, D'Orb.) ; 

 in other cases (e.g., M. pulchella, E. and H.) the corallites 

 which form the " monticules " are of a markedly larger size 

 than the average; while in still other forms (e.g., M.frondosa, 

 D'Orb.) the "monticules" in this case flat are occupied by 

 corallites much more minute in their size than those which 

 form the bulk of the colony. The so-called " maculae " are 

 simply " monticules," in which the mouths of the tubes have 

 become closed by a calcareous membrane. 



The only other point as regards the structure of the Monti- 

 culiporce which need specially be noticed here concerns the dis- 

 position of the tabulcz. These structures are invariably present 

 in the typical Monticuliporcz , and are almost invariably " com- 



