128 Mr. F. M'Coy on some new Fossil Fish 



the oblique striation crossing the ordinary punctuation of Psam- 

 modontoid teeth is a character I have not seen in any other 

 tooth. Height of crown 6 lines, width of base 5 lines, depth of 

 root 4 lines. 



From the carboniferous limestone of Armagh. 



(Col. Capt. Jones, E.N.) 



Glossodus marginatus (M'Coy). 



Sp. Char. Crown about one-third higher than wide, having a 

 slight antero-posterior sigmoidal curve ; thickness, from before 

 backwards, little more than one-fourth of the width ; lateral 

 margins subparallel, prominent on the posterior face, which is 

 gently concave in the middle ; apex narrowed, rounded, curved 

 backwards ; surface glossy, finely punctured, marked towards 

 the tip with minute anastomosing longitudinal wrinkles ; a few 

 obtuse plicse. Length of crown 5 lines, width 3 lines. 



Easily distinguished from the G. marginatus by its more 

 finely punctured, glossy surface, rounded tip and prominent 

 lateral margins. 



One of the rarest fossils of the carboniferous limestone of 

 Armagh. 



(Col. University of Cambridge ; I think T have seen another in 

 that of Capt. Jones at Dublin.) 



Climaxodus (M'Coy), n. g. 



(Etym. /cKi/tat;, a flight of steps, and 68ovs, a tooth.) 



Gen. Char. Tooth longer than wide, gradually narrowing towards 

 the front with nearly straight sides ; anterior part of the crown 

 crossed by broad, imbricating, transverse ridges at right angles 

 to its length ; surface minutely punctured. 



The above generic name has reference to the remarkable step- 

 like character of the ridges which cross the anterior part of the 

 tooth at regular intervals. The broad posterior part of the tooth 

 is without ridges and resembles a Psammodus. In the fact of 

 being as it were small, ridged Psammodi, those teeth are allied 

 to the genus Pcecilodus, but all the true Poecilodi are inequilateral, 

 mussel-shaped teeth, consequently placed in pairs in the mouth, 

 and have the ridges oblique ; the Climaxodi, on the contrary, are 

 equilateral, and were therefore most probably mesial in position, 

 and the ridging is transverse. 1 am aware of one species in the 

 Armagh limestone and the following. I think it possible that 

 the so-called Poecilodus parallelus (Ag.) may ultimately be re- 

 ferred to this genus, as it differs from the true Poecilodi in some 

 at least of the above characters. 



