408 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
antero-posteriorly expanded base of the crown gives it a slightly Helodont character. 
It may be found to occupy an intermediate position, at present it is included in the 
genus Lophodus. 
Formation and locality : Carboniferous Limestone, Wensleydale, Yorkshire. 
Hex coll. William Horne, Esq., Leyburn. 
Lophodus serratus, Davis. 
(Pl. LI, figs. 23, 24.) 
Teeth, small, narrow; transverse diameter ‘6 of an inch, antero-posteror diameter 
‘12 of an inch. Crown ascends from each lateral extremity to the central cone, 
latter pointed and somewhat beak-like with a slight curvature posteriorly ; sub- 
median ridge descends from the apex of the central cone, along each lateral pro- 
longation from which spring eight small subconical tubercles on one side and ten 
on the opposite one ; tubercles equidistant, and along with the central one uniformly 
punctate. Anterior surface of crown, convex, smooth near the base. Posterior 
surface concave, with a series of enamelled folds extending across the tooth parallel 
with its margin. 
This species is distinguished from Z. maminillaris (Ag.) to which it otherwise 
bears considerable resemblance by the tuberculation of the median coronal ridge. 
Formation and locality : Carboniferous Limestone, Wensleydale. 
Ex coll. Wm. Horne, Esq., and Reed collection, York Museum, 
Lophodus bifureatus, Davis. 
(Pl. LI, figs. 25, 25a.) 
Teeth, small ; transverse diameter across base °5 of an inch ; height °4 of an inch. 
Crown consists of large, obtusely subangular, obliquely inclined convex surface ; 
with a greatly depressed, slightly twisted, prolongation of the lateral extensions 
narrowing to subacute horizontal extremities. Anterior margin prominent ; 
surface of crown slopes backwards to the posterior margin, which is much 
elevated; basal margin of crown projects beyond the roots. Surface uniformly 
punctate. Root, short, extending to the termination of each lateral extension_of 
the crown, open porous structure, 
This unique and peculiar tooth is provisionally placed in the genus Lophodus, 
resembling in some important respects the teeth included in that genus, but the 
peculiar anterior-posterior slope of the coronal surface and the deep lateral exten- 
sions of the enamel somewhat approach the character of the genus Ramphodus, 
but in this instance the lateral extensions are equal in length, those of Ramphodus 
being unequal and the apex of the crown is not pointed as in that genus. 
Formation and locality : Carboniferous Limestone, Wensleydale, 
Ex coll. Wm. Horne, Esq., Leyburn. 
