BUB-CLASS 



TABULATA CHAETETIDAB 



103 



polygonal, all of one kind, and multiplying ly fission. Uncompleted fission of 



the tubes often indicated in section by tootlilike projection extelidilli; into 

 \isrn-al cliaml.er. Walls st nictmvless, without dark median line; tabular 

 complete, remote. Very abundant in Carbon 

 ifrrous Limestone; found also in Lias and Cppn- 

 Jurassic. I '. /W/"/<s, Fisch., is an important 

 i-ock imildrr in the Russian Carboniferous Lime 

 tone, especially iii the vicinity of Moscow. 

 Pseinln, 



Hang; - n 



Jurassic. 



Quenst. sp. 



AIoufi<'nlij'"i''i, 

 d'Orb. (emend. 

 Nichj. (Figs. 

 185-187). Mas- 

 sive, tuberous, 



Flem. Carbon ifer- 



<iiis Limestone ; England. .d, Transverse 

 sect inn parallel to upper surface. 

 /,', Vertical section, both enlarged ; 

 p, Projecting spines representing un- 

 completed fission (after Nicholson). 



184. 



Chnetetes radians, Fischer. Carbonifer- 

 ous Limestone ; Moscow, Russia. Portion 

 of longitudinally fractured corallum, 

 natural size. 



discoidal. ra- 

 mose, or en- 

 crusting coralla 



of extremely variable form and size, and composed of numerous, fine, tubular 

 corallites, usually of two series, the walls of which are imperf orate and closely 

 approximated to one another, but are not amalgamated. Multiplication by 

 intermural gemmation, more rarely by fission. Tabulae horizontal, and either 

 complete, extending entirely across the visceral chamber, or incomplete ; in the 

 latter case the spaces where tabulae are not developed are filled with 



(lli-ti'rntr.'/pi') rl,x..-", K. Mill 



H. Onloviciai 



(Cincinnati Group); Cincinnati, Ohio. 



.1. Ciiialluin, natural sixe. /;, Surface slightly niaunilicd. (', Tangential section, parallel to external surface, 

 ^ /, V.-rtiwil section, ---o/i. C'""'! /'after Xicholson.) 



cystoid calcareous plates. The walls differ from those of Cfmetetes in that they 

 are composed of two distinct lamellae separated by a dark or light median line, 

 and are sometimes thickened by deposits of carbonate of lime. The corallites 

 are polygonal or round in contour, and, as a rule, two series are distinguishable : 

 a series of larger tubes with remotely situated tabulae, and another series of more 

 or less numerous interstitial tubes, which are smaller and more closely tabulate 

 than the former. The larger tubes (autopores) are often surrounded on all sides 



