ICHTHTQDQRU LITES. 
149 
denticles of the concave margin appear to be directly con¬ 
tinuous with the lateral ribs. 
Presented by Prof. L. G. de Koninclc, 1876. 
The following species have also been described :— 
Listracanthus beyrichi, A. von Koenen, Neues Jahrb. 1879, I 
p. 341, pi. vii. fig. 1: Pamphr actus Jiydrophilus, H. Hey- 
mann ( errore ), Sitzungsb. niederrhein. Gesell. 1870, 
p. 217.—Culm-Measures ; Herborn, Nassau. 
Listracanthus hilclrethi, J. S. hewberry, Rep. Geol. Surv. Ohio, 
vol. ii. pt. ii. (1875), p. 56, pi. lix. fig. 6.—Carboniferous; 
Ohio. [Marietta College, Ohio.] 
% 
A species of this genus from the Calciferous Sandstones of East 
Kilbride, Lanarkshire, is also preserved in the collection of Dr. 
John Hunter, Braidwood, near Carluke. 
Genus BYSSACANTHUS, Agassiz. ^ ^ 
[Poiss. Foss. Yieux Gres Rouge, 1845, x>p, 111, 116.] AS’—* 
Basal portion of spine broad, not deeply inserted, with a large 
central cavity, tapering above and passing into a cylindrical elon¬ 
gated portion, straight or slightly arched, with a blunt apex. The 
surface of the cylindrical portion ornamented with coarse longitu¬ 
dinal ridges, diverging and fewer upon the broad basal portion. 
Byssacanthus crenulatus, Agassiz. 
1845. Byssacanthus crenulatus , L. Agassiz, op. cit. pp. Ill, 116, 
pi. xxxiii. figs. 11-14. 
1860. Byssacanthus crenulatus, E. von Eichwald, Leth. Rossica, vol. i. 
p. 1598. 
Type. Keyserling Collection. 
The type species. 
Form. 4' Loc. Devonian : St. Petersburg, Russia. 
P. 2251. Two fragments. Eyerton Coll . 
< 
The following species have also been described, but there are no 
examples in the Collection :— , 
Byssacanthus arcuatus, L. Agassiz, Poiss, Eoss. Y. G. R. (1845), 
p. Ill : Onchus arcuatus , L. Agassiz, Poiss. Foss. vol. iii. 
