'39 



CHAPTER V. 



GENERA OF FAVOSITID/E {cOUtUmcd). 



Genus MicHELiNiA, De Koninck, 1842. 

 (An. foss. des terr. Carb. de le Belgique, p. 29.) 



Gen. C/iai^ — Corallum forming hemispherical, depressed, or 

 pyriform masses, often of considerable size, composed of pris- 

 matic or subcylindrical corallites, in close contact throughout 

 their entire length. Walls not thickened to any unusual extent, 

 perforated by numerous mural pores, which are often multi- 

 serial, and have no definite arrangement. Calices polygonal or 

 subcylindrical, not surrounded by thickened margins. Tabula; 

 numerous, generally more or less curved with their convexities 

 upwards ; usually anastomosing with one another to a greater 

 or less extent, so as to give rise to a loose and open vesicular 

 tissue ; and often carrying numerous vertically-directed spin- 

 ules. Septa represented by numerous radiately - arranged 

 longitudinal striae, ridges, or vertical rows of tubercles, varying 

 in number from twenty-five to forty. Under surface covered 

 by a concentrically-striated epitheca, which may or may not be 

 provided with hollow radiciform prolongations. 



Obs. — This well - known genus comprises a number of 

 Devonian and Carboniferous corals, which present a close 

 general resemblance to the larger forms of Favosiics. The 

 corallum (fig. 21) is massive, usually more or less hemispheri- 



