396 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
branch out anteriorly and posteriorly, each speedily bifurcating and afterwards 
encircling the base of the crown after the manner of a chain. Root deeper than 
the height of the crown ; anteriorly prominently convex ; posteriorly concave ; usual 
porous structure. 
This species appears to be sufficiently distinguished by its surface ornament and 
small size. There is always the possibility that small specimens may be the teeth 
of young fishes of other species, but in this instance such a probability is remote. 
The teeth were named by Prof. Agassiz but not described or figured. 
Formation and locality : Mountain Limestone, Armagh. 
Ex coll, Karl of Enniskillen ; and Museum, Geological Society. 
Orodus gibbus, Agass. (MSS.) 
(Pl. LL, figs. 6, 7.) 
Orodus gibbus—L, Agassiz “ MSS., Capt. Jones’ Collection, Geol., Soc., London.” 
- “5 Portlock, 1843. “Report Geol., Londonderry, &c.,” p. 461. 
3 s J. Morris, 1854. “Cat. Brit. Foss.,” p. 335. 
55 be Morris and Roberts, 1862. “Quart. Journ. Geol. Soc.,” Vol. NOWIVOE fo OL, 
< 3 J. J. Bigsby, 1878. “Thesaurus Devonico-Carb.,” p. 359. 
Teeth, medium size, peculiar humpy form ; transverse diameter 1-1 inch ; antero- 
posterior diameter of central cone ‘35 of an inch; lateral portions about half the 
diameter of the central cone, with one or more secondary cones on each side; 
lateral terminations obtusely rounded; base of crown much contracted antero- 
posteriorly ; central cone large, gibbous, expanded prominently before and behind, 
overhanging the base. The coronal surface contracts abruptly on each side for a 
distance equalling the diameter of the median cone, when it becomes again ex- 
panded to form secondary cones; occasionally there are two secondary cones on 
one or both lateral extensions ; surface smooth, uniformly punctate; base of the 
crown slightly crenulated. Root equal in depth to the height of the crown and 
co-extensive laterally; coarse spongy texture; anteriorly convex; posteriorly 
deeply concave; under-surface smooth. 
The species, by its gibbous form, is readily distinguished. There are a number 
of specimens in the collection of Lord Enniskillen which appear to belong to this 
species, they are not so regular in form as the types, and are much worn apparently 
by attrition, the cones being reduced almost to the level of the remaining portion 
of the tooth. One specimen affords evidence of having possessed a row of small 
tubercles along the anterior basal margin of the crown. 
Formation and locality: Mountain Limestone, Armagh. 
4x coll. Karl of Enniskillen, Museum of Geological Society. 
Orodus sculptus, Davis 
(Pl. LI, figs. 8, 8a.) 
Teeth, medium size ; transverse diameter 1°3 inches; from anterior to posterior 
