On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 407 
Lophodus didymus, Agass. 
(PL Ibh, snags, Oath, Bila.) 
Helodus didymus—L. Agassiz, 1838. ‘ Poiss. Foss.,” Vol. III., pp. 173 and 383. 
ss - J. E. Portlock, 1845. <‘ Rept. Geol. of Londonderry,” p. 461. 
Es >» C. G. Giebel, 1848. ‘ Fauna der Vorwelt,” Vol. I., pt. 3. p. 341. 
3 5 H. G. Bronn, 1848. “ Nomencl. Paleont.,” p. 583. 
a5 ¥s 1849. ‘ Enumerator Palzont.,” p. 647. 
» 7" J. Morris, 1854. “Cat. Brit. Foss.,” p. 328. 
D 5 F. J. Pictet, 1854, “ Traité de Paléont.,” Vol. IT., p. 267. 
rs ; F. M‘Coy, 1855. “ Brit. Palzoz. Foss.,” p. 630, pl 3L., figs. 18, 19, 20. 
Morris and Roberts, 1862. “ Quart. Journ. Geol. Soc.,” Vol. XVIIL., p. 100. 
H. Rowanowsky, 1864. ‘Bull. Soc. Imp. des Nat. de Moscou,” p. 162, pl. iv., 
fig. 23. 
‘“‘'Thesaurus Devonico-Carb.,” p. 357. 
DM 
J. J. Bigsby, 187 
Teeth, “Crown of tooth usually much elevated in the middle into a very pro- 
minent cone, more or less deeply notched at the apex, and having from that notch 
a more or less distinct sulcus extending towards the base of the crown, the border 
of which is elevated in the middle, particularly the posterior side close to, or 
vertically over which, the double apices of the cone usually incline. Surface, 
coarsely granulo-punctate, most so on the end of the middle cone, leaving the ends 
of the tooth nearly smooth (the granules being closed and elevated in the unworn 
tooth, but impressed punctate in old ones), width of average or rather small specimen 
four lines, height two and a half lines, but sometimes more, and often less.”— 
(M‘Coy.) The root is small, compressed and vertically striated. 
Formation and locality : Mountain Limestone, Armagh. 
Ez coll. Kar] of Enniskillen. 
Lophodus reticulatus, Davis. 
(PH, Willey step, 22.) 
Teeth, transverse diameter 1°3 inches; antero-posterior diameter °3 of an inch 
in the widest median portion. Crown generally depressed, produced to form a 
median cone with a large secondary cone on each side and smaller intermediate 
ones. Principal cone situated nearer one end than the other, obtusely pointed, 
broader laterally than from front to back: a carina extends from central cone on 
each side, from which rise the lateral ones similar in character to the median one; 
lateral terminations of crown truncate. Surface of cones, smooth, punctate ; 
anterior and posterior surface expanded and depressed, reticulate ; posterior margin 
produced and forming a thick and rounded ridge. Base, hidden by matrix. 
The characters of the type specimen of this species are somewhat indeterminate. 
Its surface possesses a median ridge with cones which ally it to Orodus, whilst the 
TRANS, ROY. DUB. SOC., N.S., VOL. I. 63 Gn 
