DEVONIAN AGE. 



259 



&f an inch in diameter, marked with eight spiral ridges, which he regards as seeds of a 

 Chara. These frequently occur also in the cellular chert at the Falls of the Ohio. 



2. Animals. 

 The Corniferous period was, as has been stated, eminently the coral- 

 reef period of Paleozoic time. 



1. Invertebrates. — The existence of Sponges is indicated by the 



Figs. 485-491. 

 487 



Fig. 492. 



Polyps. — Fig. 485, Zaphrentis gigantea; 486, Z. Rafinesquii ; 487, Phillipsastrea Verneuili 



488 a, Cyathophyllum rugosum ; 489, Favosites Goldfussi ; 490, Syringopora Maclurii ; 491, 

 Aulopora cornuta. 



presence of their siliceous spicula in the hornstone, two slender forms 

 of which are shown in Figs. 484 A,j, k, page 257, and others in /, m, n. 



Figures 485 to 491 represent some of the corals ; 

 486 shows well the radiated cup-shaped termination 

 to which the name Cyathophylloid corals (from kvcl- 

 0os, cup, and <f>v\\.oi', leaf) refers ; 485 has both 

 extremities broken off, but exhibits the interior radia- 

 tion ; 489 is a portion of a common species of Favo- 

 sites (honey-comb coral, named from favus, honey- 

 comb), a kind that sometimes occurs in hemispheres 

 five feet in diameter ; 487 is part of the surface of 

 a common massive coral. 



Among Echinoderms, the most interesting are species of the group 

 of Blastids, or Bud-Crinoids, having no proper arms, one of which is 



Nucleocrinus Ve 

 neuili. 



