PALEOZOIC TIME — DEVONIAN. 



583 



The higher Cryptogams, or Acrogens, are represented by Lycopods, or 

 Oround Pines, Ferns, and Equiseta. 



To the Lycopod tribe are referred species of PsilopJiyton, similar to those 

 of the Oriskany period ; portions of the plant are shown in Figs. 854 a, 6, and 



853. 



MioEoscopic Organisms in Hoknstone. — Figs, a-i, Protophytes ; j-n, spicules of Sponges ; o, p, Annelid jaws. 



its fructification in c, d. They were one to three feet high. The species 

 differ from the common Ground Pine in having the leaves on the stems nearly 

 "wanting, and also in having the axis made up of scalariform vessels, and the 

 spore-cases (fruit, c, d) usually in pairs on short pedicels. 



854-857. 



855 



Lycopods. — Figs. 854 a, b, Psilophyton princeps ; c, d, same, fruit ; 855 a, Lepidodendron Gaspianum (1) ; b, 

 same, showing surface scars of lower part of stem. Ferns. — Fig. 856, Sphenophyllum yetustum (1) ; 85T, 

 stem of tree fern, CauJopteris antiqua (x ^). Figs. 854, 855, Dawson ; 856, 857, Newberry. 



The Comiferous limestone of Ohio has afforded the Ferns, Figs. 856 and 

 857, described by Newberry. The latter is part of the trunk of a tree fern 



