120 SILUKIA. [Chap. VI. 
In addition to the nniversal Chain-coral (Halysites catennlarius, Foss. 
20. f. 6) and the Favosites fibrosns (Foss. 18, f. 7), which are often met 
Fossils (19). Corals op the Wenlock Limestone. 
Millepore Corals of the genus Heliolites, most nearly related to the ' Blue Coral ' Helio- 
pora cserulea, Blainv.) of the Australian coral-reefs. 
1. Heliolites tubulatus, Lonsd. 2. H. petaliformis, Lonsd. 3. H. interstinctus, Wahl. ; 
a variety with large tubes. 4, 5. H. interstinctus, Wahl. ; ordinary variety. 
Fossils (20). Corals &c. op the Wenlock Limestone. 
1. Diastopora ? consimilis, Lonsd. 2. Young of Syringopora bifurcata, Lonsd. 3. 
Coenites juniperinus, Eichw. 4, 5. Syringopora bifurcata, Lonsd. 6. Halysites catenu- 
larius, Linn. 
with in the Lower Silurian rocks (see Chap. IX.), the following species of 
Corals are everywhere typical of the Wenlock Limestone : — 
Heliolites interstinctus, Foss. 19. f. 3, 4, 5, both the large- and small-celled varieties ; 
H. tubulatus, f . 1 ; H. petaliformis, f. 2 ; Favosites asper, Foss. 18. f. 4 ; F. cristatus; 
f. 1 ; Coenites juniperinus, Foss. 20. f. 3 ; Syringopora bifurcata, f. 4, 5, and its young 
or creeping form (Aulopora serpens, Sil. Syst.), f. 2 ; Omphyma turbinata and O. sub- 
turbinata (see Chap. X.) ; Alveolites Labechii, Edw. ; Cyathophyllum truncatum, Linn., 
and C. articulatum, Wahl. ; Acervularia luxurians, Eichw., with many others*. 
Of the Crinoids, the more perfect only of the forms published in my old 
work are reproduced in the plates of this volume. Perhaps the large 
* In the above three woodcuts some of the most divided into three genera; whilst a few of the 
frequent Corals of the limestone are figured. Here, species are still regarded as being identical with 
as in the subsequent chapters on organic remains, Devonian forms. See M'Coy's Description of the 
the nomenclature differs in a rare instance only British Palaeozoic Fossils in the Geological (Wood- 
from that of Milne-Edwards and Haime (' Poly- wardian) Museum of the University of Cambridge, 
piers Fossiles ')• Thus the genus Heliolites is not 
