GENERA OF FAVOSITID^E. 155 



Chonostegites Clappi, Edwards and Haime. 

 (PL VIII., figs. 2-2 c.) 



Chonostegites Clappi, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., 



p. 299, 1851. 



Michelinia intermittens, Billings, Canad. Journ., new ser., vol. iv. p. 113, 1859. 

 Haimeophyllum inordinatum, Billings, Canad. Journ., new ser., vol. iv. p. 



139, fig. 29, 1859. 

 Michelinia Clappi, Rominger, Foss. Cor. of Michigan, p. 75, PL XXVIIL, 



figs. 3 and 4, 1876. 



Spec. Char. Corallum often of considerable size, composed 

 of subparallel, essentially circular, tubular corallites, which are 

 for the most part free, though sometimes partially in contact, 

 in which latter case they become more or less polygonal by 

 mutual pressure. In parts where they are in contact the walls 

 of the corallites are perforated by numerous irregularly-distri- 

 buted mural pores, which place the visceral chambers of con- 

 tiguous tubes in direct communication. When they are not in 

 contact, the corallites are individually enclosed in a distinct 

 epitheca, which is not perforated, and which is marked with 

 numerous fine encircling strise. Where not in contact, also, 

 the corallites are annulated by numerous alternate constrictions 

 and dilatations, giving to each the appearance of a succession 

 of funnels vertically superimposed upon one another. The 

 dilatations of contiguous tubes are placed more or less at the 

 same levels, and unite with one another, so as to form a succes- 

 sion of concentrically superposed floors, which can be shown to 

 be hollow, and thus to place the visceral chambers of neigh- 

 bouring tubes in actual communication. Viewed from above, 

 the calices are seen to be circular, and to be surrounded at a 

 little distance by faintly-marked polygons inscribed on the 

 upper surface of the connecting-floors. Tabulae numerous, 

 arched, inosculating to a greater or less extent, and forming 

 large lenticular cells, which are continued into the hollow hori- 

 zontal connecting-floors. Septa in the form of short spines 

 arranged in vertical rows. The upper surfaces of the tabulae 



