360 G. J. HINDE ON CAMBRO-SILURIAN 
long, nearly straight, cylindrical, blunted, main tooth, on one side of 
which are two blunted denticles with small knobs at their summits. 
Length of main tooth 3 line, of the base line. 
Loc. North Evans, New York: from the ‘“Conodont-bed” of 
the Hamilton group. 
Prionropus cLAvaTusS, Hinde. (PI. XY. fig. 16.) 
Basal portion arched, narrow, stout and convex in section; the 
central tooth straight, cylindrical, and blunted; on one side of this 
there are four, and on the other two stout teeth similar to the cen- 
tral tooth and but little inferior in size. 
Length of base 3 line, of the central tooth 2 line. 
Loc. North Evans, New York: from the “Conodont-bed ” of the 
Hamilton group. 
Prionropus aNauLatus, Hinde. (PI. XY. fig. 17.) 
Base thin, narrow, and arched, so that the two sides meet at an acute 
angle ; from the apex there rises a long, straight, compressed, needle- 
shaped main tooth with a median longitudinal groove; on either 
side of the base are four slightly curved slender denticles. Distance 
between extremities of the base 4 line; length of main tooth 4 line. 
This species is very delicate and brittle, and perfect examples are 
rare. The missing portions, however, leave their impressions in the 
shale, so that the entire form can be readily distinguished. 
Loc. North Kvans, New York: from Genesee Shale. Also at 
Bedford, Ohio: in Cleveland Shales, Lower Carboniferous. 
PRIONIODUS ACICULARIS, Hinde. (PI. XV. figs. ikesy US») 
Basal portion straight or slightly arched, generally wide, very 
thin, polished and transparent; near one extremity a relatively 
large, slightly curved, compressed main tooth, with two denticles on 
one side, and on the other aseries of from eleven to thirteen delicate, 
slightly curved, acutely pointed denticles, slightly inclined to the 
base in which they are imbedded. The main tooth and the denticles 
have a polished aspect and tint like ivory, whilst the base is of a 
brownish horn-colour. In fig. 18 the length of the base is % line, 
and of the main tooth 3 line; in fig. 19 the base is 1 line and the 
main tooth Z line in length. 
The base is very variable in width in different examples, and in some 
forms the two denticles preceding the main tooth are not present. 
Loe. Kettle Point and Bear Creek, Lambton County, Ontario; 
North Evans, New York: Genesee Shale. 
Priontopus ArMAtUs, Hinde. (PI. XV. figs. 20, 21.) 
Basal portion very narrow and slightly curved; at one extremity 
a relatively large, triangular, depressed convex main tooth, the ex- 
terior basal angle of which is produced downwards into a short 
spur. There are from five to eleven straight compressed denticles. 
Length of base from 4 line to ? line, of the main tooth 3 line. 
Loc. Near Port Stanley, Lake Erie, Ontario: in erratic boulders 
