146 



HISTORICAL PAL/EOXTOLOGY. 



fan-like or funnel-shaped form, which grew attached by its 

 base to some foreign body. The frond consists of slightly- 



Fig-. 90. — Fragment of Clathropora intertexta, of the 

 natura' size and enlarged. Devonian, Canada. (Orig;inal.) 



Fig. 91. — Fragment of 

 Cericpora Hamiltone7isis, of 

 the natural size and enlarg- 

 ed. Devonian, Canada. (Ori- 

 ginal.) 



diverging or nearly parallel branches, which are either united 

 by de-licate cross-bars, or which bend alternately from side to 

 side, and become directly united with one another at short 

 intervals — in either case giving origin to numerous oval or 



Fig. 92. — Fragment of Fefiesiella -niagnifica, 

 of the natural size and enlarged. Devonian, 

 Canada. (Original.) 



Fig. 93. — Fragment of Retepora 

 PhilUpsi, of the natural size and 

 enlarged. Devonian, Canada. (Ori- 

 ginal.) 



fit. 



Fig. 94. — Fragment of Fenestella 

 cribrosa, of the natural size and enlarg- 

 ed. Devonian, Canada. (Original.) 



oblong perforations, which communicate to the whole plant- 

 like colony a characteristic netted and lace-like appearance. 

 On one of its surfaces — sometimes the internal, sometimes the 

 external — the frond carries a number of minute chambers or 



