448 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britaan. 
Xystrodus striatus, Agass., MSS. 
GPL IOI, te Vy 8 D> 104) 
Cochliodus striatus—L. Agassiz, 1838. <“‘ Rech, sur les Poiss. Foss.,” Vol. ILI., p. 174. 
5 5 J. E. Portlock, 1843. ‘Rept. Geol. Londonderry, &c.,” p. 461. 
5 % C. G. Giebel, 1848. “ Fauna der Vorwelt,” Vol I., pt. 3, p. 336. © 
es Ps H. G. Bronn, 1848. <‘Nomencl. Paleont.,” p. 317. 
ts ¥ 55 1849. ‘“ Enumerator Paleont.,” p. 647. 
a - J. Morris, 1854. ‘Catal. Brit. Foss.,” p. 322 
5 $5 F. J. Pictet, 1854, “Traité de Paléont., Vol. IJ., p. 267. 
i FS F. M‘Coy, 1855. “ Brit. Paleeoz. Foss,” p. 624, pl. 3 I, fig. 27. 
Xystrodus striatus—L. Agassiz, 1859. “MSS. Enniskillen Collection. 
5 . Morris and Roberts, 1862. ‘Quart. Journ. Geol. Soc.,” Vol. XVIIT., p. 101, 
Fe 43 Enniskillen, 1869. “Cat. Types Foss. Fishes,” p. 9. 
Aymstrong, Young, ) ‘ » 
» 1 ne Robertson, f 1876. “Cat. W. Scot. Foss.,” 63. 
* 5 J. J. Bigsby, 1878. ‘Thesaurus Dey.-Carb.,” p. 367. 
«Terminal tooth aliform, triangular, very much broader than long ; long articular 
margin forming an angle of about 35° with the outer edge; along this articular 
margin is the most prominent part of the surface, forming an obtusely rounded, 
slightly sigmoid ridge ; the remainder of the surface being flattened and extending 
with a slight concavity to the terminal point, which is nearly rectangular and 
obtuse. Surface with a fine sharp, granulo-punctation having the usual quin- 
cuncial arrangement on the long obtuse convexity of the articular ridge, and on 
the opposite, flattened, terminal angle; but on all the intermediate portion the 
puncte tall into regular, slightly flexuous lines, extending longitudinally nearly at 
right angles to the articular side ; about twelve of the lines of punctures in a 
space of one line.”—(J/‘Coy.) 
The number of teeth comprised in the above description by Prof. M‘Coy has 
been greatly amplified since he penned the description, and asa result, a comparison 
of the teeth in Lord Enniskillen’s collection proves either that there are two or three 
species, or that some of the teeth are from the upper, and others of different form 
from the lower jaws. Prof. Agassiz regarded them as different species, and, there 
being not the ieast evidence to the contrary, they will be regarded as separate 
species at present. The Xystrodus striatus (Cochliodus striatus, M‘Coy) 
consists of teeth, as stated in the description above, whose surface punctation falls 
into lines roughly parallel with the posterior margin of the tooth. The teeth 
are somewhat different in form to those described by M‘Coy, an average specimen 
being *6 inch along the raised articular margin, and an equal length across 
the posterior face, whilst the longest side is ‘9 inch in length. The anterior 
margin is considerably inrolled and in this bears some resemblance to the upper 
tooth of Deltodus sublevis, as well as in its apparent method of growth. The 
