382 G. J. HINDE ON ANNELID JAWS FROM 
Cinonrres ampius, Hinde. (PI. XIX. fig. 23.) 
Jaw elongated, nearly straight and flat, relatively wide, and 
blunted posteriorly; the anterior tooth is partly wanting in the 
specimen, but it appears to have been slightly curved and larger 
than the others. Following the first are seven prominent, acutely 
pointed, conical teeth, and these are succeeded by another series of 
similarly shaped, but very minute, teeth. Length % line, and line 
wide. 
Clinton formation. 
CinonirEs FRAGILIS, Hinde. (Pl. XX. fig. 3.) 
Jaw oblong, short, truncate, and flattened, with a furrow just 
below the toothed edge in the posterior half of the jaw; the first six 
teeth are blunted and subequal, followed by six minute teeth. 
Length ? line, about } line in width. 
Though this example differs from the more typical forms of the 
genus in the absence of a larger tooth or hook in front, in other 
respects it appears to resemble this genus in possessing a flattened 
surface and truncated extremity with the usual furrow. 
Clinton formation. 
CENONITES ? INFREQUENS, Hinde. (Pl. XX. fig. 2.) 
Jaw elongated, relatively wide, and shghtly concave, with the 
posterior extremity blunted; the front tooth or hook, which has 
been partly broken off in the specimen, appears to have been nearly 
upright; on the straight upper edge of the jaw are about twenty- 
five, very minute, conical, upright teeth. Length 17 line, and } line 
wide. 
Though this form differs considerably from the typical species of 
this genus, it appears more closely related to it than to Hwnicites. 
Niagara formation. 
ARABELLITES ELEGANS, Hinde. (Pl. XX. figs. 5 & 7.) 
Jaw flattened, widest in the central portion, with a small protu- 
berance below, a similar one at the narrow posterior extremity, and 
a depressed groove below the toothed edge; a large and slightly 
curved hook in front, and about eleven teeth on the crest of the 
main portion, the first six of which are pointed and subequal, the 
others very minute and blunted. Length 2 line, greatest width 
z line. In the same beds is a much smaller form with only six 
minute, scarcely discernible, teeth, and the anterior hook in propor- 
tion. Length of this example 2 line. 
This species is closely related to A. cornutus from the Cincinnati 
group ; but the hook is less proportionately developed, and the jaw 
itself is of very much smaller dimensions. 
Clinton formation. 
ARABELLITES stuItis, Hinde. (Pl. XX. fig. 8.) 
Jaw very minute, somewhat triangular in form, the pointed ex- 
tremity nearly below the centre of the jaw, the upper border slight ly 
