88 DESCRIPTIONS OF THE REMAINS OF FISHES 
2. COCHLIODUS OCCIDENTALIS, Leidy. 
This species is proposed on eight more or less imperfect specimens of teeth. In their 
perfect condition, the teeth have a trilateral outline; are strongly curved transversely; and 
have the outer extremity narrow, the inner border convex, the anterior part recurved, and 
the posterior border thick and slightly concave. The posterior two-thirds of the tritu- 
rating surface are prominently convex and smooth, or wrinkled transversely or longitudi- 
nally. Structure coarsely porous. Antero-posterior diameter from eight lines to nearly 
an inch; transverse diameter from eight lines to one and a quarter inches. 
Locality.—Carboniferous limestone of Warsaw, Illinois. Besides the preceding spe- 
cimens there were discovered in the same locality fragments of six larger teeth, which are 
too imperfect to judge of their form. Possessing the same structure as those just de- 
scribed, they may probably be the middle teeth of the series in the jaws. ‘The largest of 
the specimens is three lines thick, and all appear as if they might be the greater portion 
of trilateral plates. Their triturating surface is moderately convex and smooth, or slightly 
wrinkled. At one broken border it appears as if it were recurved, and at the opposite bor- 
der it turns downwards at right angles, and what is probably the inner border is thick 
and convex. 
Plate V., Figs. 3—10. Teeth of Cochliodus occidentalis. Figs. 11—16. Six fragments 
of teeth last referred to in the above description, and probably belonging to C. occidentalis. 
3. CocHLiopus LAtus, Leidy. 
This species is proposed on a fragment of a large tooth, apparently a second of the se- 
ries in the jaw. In its perfect condition the tooth has been over two inches in length, 
and more than one and a half in breadth. The triturating surface presents two oblique 
convexities separated by a shallow depression, and there may have been a third ridge at 
the anterior border. The postero-internal angle of the specimen is abruptly bevelled off, 
apparently as the result of wearing. ‘The structure is coarsely porous. 
Locality — With the preceding species. 
Plate V., Fig.17. Tooth of Cochliodus latus ; the margins of the specimen being broken. 
= HELODUS AG. 
4. Hetopus cissus, Leidy. 
This species is proposed on a single and imperfect specimen of a tooth, which in the 
fragment exhibits a prominent gibbosity obscurely divided into two. Surface coarsely po- 
rous. Height of crown three lines; probable length when perfect one and a quarter 
inches; probable breadth in the same condition seven and a half lines. 
Lccality—The Carboniferous limestone of Warsaw, Illinois. Plate V., Fig. 18. 
