GENERA OF FAVOSITID.E. 73 



form of lobate pyriform masses, which, when young, are from an 

 inch to two inches in height, with a diameter of half an inch to 

 an inch. Sometimes they terminate above in a simply dilated 

 and undivided upper surface, which may be slightly convex or 

 nearly flat ; but at other times they split up superiorly into two 

 or more lobate divisions. Older examples, with or without 

 proportionate increase in height, may become massive, till we 

 get coralla, of variable, but most generally of obconical shape, 

 which may be three or four inches in diameter at their summit. 

 While branching of the corallum is quite common, I have not 

 personally met with so completely dendroid a specimen as one 

 of those figured by Edwards and Haime (Brit. Foss. Corals, 

 PI. LXIIL, fig. i). The lower and outer surface of the coral- 

 lum does not appear to be covered with a regular epitheca — at 

 least I have not observed such a structure ; but the lonof irregf- 

 ularly prismatic corallites pass upwards from the base of at- 

 tachment, diverging as they go in such a manner that a side 

 view exhibits the walls of the corallites, broken at tolerably 

 regular intervals by recurrent spaces or ledges occupied by 

 open calices. This feature is one very characteristic of the 

 pyriform examples of this species, but in all forms alike the 

 uppermost surface is occupied by the calices. 



Milne- Edwards and Haime referred this species with doubt 

 to ChcBtetes or Monticulipora, and of its close resemblance to 

 these genera there can be no question. Vertical sections, suit- 

 able for microscopic examination, bring into view, however, a 

 well-developed series of mural pores, and thus prove conclu- 

 sively that the species is truly referable to Favosites (PI. III., 

 fig. 4 U). The pores are irregularly distributed, and seem to be 

 generally in two or three series, their size always being small. 

 They are very abundant and conspicuous in Swedish examples, 

 and, for some reason, appear to be much fewer in number in 

 British specimens, though still quite determinable with a little 

 care. It is worthy of note, in this connection, that though the 

 existence of mural pores can usually be recognised in thin 

 sections without any difficulty, I have never succeeded in de- 



