256 THE MEDALS OF CREATION. Cuap. VII, — 
M. Barrande divides the Graptolites into three groups or 
genera, which are defined as follow :— 
Graptolites (proper), a single series of cells united together 
at the base, and adhering along the sides nearly to the orifice 
of each cell, as in fig. la. Monoprion of M. Barrande. 
Rastrites—The axis reduced to a mere line, on which the 
cells are placed at relatively wide intervals, and but slightly 
inclined. These two genera are supposed to have been bys 
droid zoophytes, and elated to the Sertularide. 
Diprion (Diplograpsus of Mr. McCoy), cells in two series 
arranged along a central axis; these forms present a folia- 
ceous appearance; they are presumed to resemble the exist- 
ing genera Pennatula and Virgularia. 
Graptolites have been found in strata of the same age in 
Norway, Sweden, and Scotland.* I have received slates 
literally covered with them, from the Silurian rocks of. the 
United States, by the kindness of my friend, Benjamin Sil- 
liman, jun. Esq. 
Sir R. Murchison remarks, that the nature of the strata 
in which these remains occur in Radnorshire, indicates a 
condition of the sea, well suited to the habits of the family 
of Pennatulide, or Sea-pens; for the recent species live in | 
mud and slimy sediment, and the fossils are imbedded in a — 
finely levigated mud-stone, which, from its structure, must 
have been tranquilly deposited. 
I will next describe the single lamellated Anthozoa, and 
afterwards notice those corals which consist of an aggrega-— 
tion of radiated cells, either frondescent, or disposed in solid 
masses. 
Funeta (Wond. p. 623).—The corals thus named, from 
their supposed resemblance to fungi, are of a depressed form, — i 
* Many species of Graptolites from the Lower Silurian rocks of ! 
the South of Scotland, are described and figured by Mr. Harkness in : 
Geol. Journal for 1850, vol. vii. p. 58, pl. 1. 
BSS 
