98 THE GENUS MONTICULIPORA. 



areas (" macula; "), which are occupied by the smaller tubes, 

 and which are surrounded each by a radiating circle of short 

 elevated ridges carrying large tubes. The large tubes also 

 occupy, mainly or wholly, the spaces between the star-shaped 

 monticules, and each is oval or circular in shape, and surrounded 

 by a strong and thickened wall, the intervals between them 

 being occupied by the smaller tubes. The large corallites are 

 traversed by a few remote tabulse, and the small tubes are 

 closely tabulate, their tabulae often becoming sub-vesicular, 

 while their walls become obsolete. 



In its general structure, Constcllaria, Dana, makes a very 

 near approach to Fistidipora, M'Coy, and it is still doubtful if 

 the two can be separated from one another. If they should be 

 united, it is the name Fistulipora which must be abandoned, 

 as of later date than Constcllaria. The most obvious feature 

 which separates the latter from the genus Fistulipora is its 

 possession of the conspicuous star- shaped monticules which 

 adorn the surface of the corallum. There are, however, various 

 features in its internal structure which have been, as yet, im- 

 perfectly worked out, and I do not feel able at present to give 

 any definite opinion as to the extent to which it really differs 

 from Fistulipora, M'Coy. 



So far as known, the species of Constcllaria are confined 

 exclusively to the Lower and Upper Silurian deposits. 



(III.) Dekayia, Edwards and Haime, 185 i. 



(Pol. Foss. des Terr. Pal., p. 277.) 



The name oi Dekayia was proposed by Milne-Edwards and 

 Haime for a little group of Monticuliporoids, distinguished 

 from allied types only by superficial characters, and therefore, 

 fundamentally, of no more than sub-generic value. In the gen- 

 eral nature and structure of the corallum the species of De- 

 kayia entirely resemble the dendroid forms of Mo7iticulipora, 

 and the only feature that would strike the observer is that the 



