lx DESCRIPTIVE REMARKS. 
firmed by Professor Heer; they were originally described by Professor 
Haughton under the name of Knorria dichotoma. The strata in which 
they are found although lithologically resembling the Carboniferous 
state, was considered by the late Professor Jukes to belong to the Upper 
Old Red Sandstone series.* 
Although several of the Silurian and Devonian genera are the 
same, the species are for the most part distinct; Stromatopora concen- 
trica, Pl. xxix., fig. 1, and S. placenta, fig. 2, characteristic fossils of 
the Middle Devonian (Torquay group), were formerly classed with 
Corals, but are now included under the class Amorphozoa in the order 
Foraminifera. ! 
Corats (Actinozoa), are very frequent in the Middle Devonian 
limestone of South Devon, especially at Torquay, Plymouth and New- 
ton Bushel; when cut and polished, the structure is clearly shown, and 
they are frequently used for ornamental purposes. Professors Milne, 
Edwards, and M. Jules Haime, whose learned and beautifully illus- 
trated Monographs on this class of fossils in the volumes of the Pa- 
leeontographical Society we have frequent occasion to quote from, 
observes that nearly all the Devonian are distinguished from the Silurian 
Corals. Some of the most characteristic of these Devonian Corals are 
figured on Pl. xxix. 
In the Monograph on British Devonian Corals,} the authors state 
that ‘‘ the Corals of the Devonian formation in different parts of the 
world belong to about 150 well defined species, forty-six of which 
have been met with in England. The Corals belonging to the family 
Cyathophyllide are very predominant, and form thirty-three of the forty- 
six above mentioned species. The family of Favositide is represented 
by ten species, and the three remaining species belong one to each of 
the three families Stawride ; Milleporide and Poritide, with the excep- 
tion of one species all these fossils belong, therefore, to the two sub- 
orders, Zoantharia tabulata and Z. rugosa, one of which has no repre- 
sentatives in the actual Fauna, nor in the Tertiary and Secondary 
Formations. Three of these Devonian fossils exist also in the Silurian 
rocks, but all the others appear to be peculiar to the Devonian period.” 
The family Illeporide is represented by Helolites porosa, figured 
on Plate xxix., 4 a, 6, a characteristic Coral of the Middle Devonian 
limestone at the localities specified in the explanation of the Plates. 
The Favositide includes F. polymorpha (fig. 5, on the same plate), 
one of the most frequent of all the Devonian Corals. 
The remarkable Coral Pleurodictyum problematicum of Goldfuss, we 
have also figured on the same plate, fig. 3, a-d. It is referred by the 
* In the Table of Old Red Sandstone and Devonian fossils, by Mr. Etheridge, before 
referred to, plants under this name of Aynorria dichotoma (Haughton), are stated to 
oceur in the Baggy and Pilton groups of the Upper Devonian, North Devon. Possibly 
they are like the specimens figured and described by Professor Haughton, the upper 
branches of Sagenaria Veltheimiana or S. Bailyana. 
+ Palceontographical Society, 1853, p. 211. 
