422 # 
PALAEONTOLOGY OF NEW-YORK. 
Ceratiocaiis acuminatus (n. s.). 
Plate LXXXIY. Fig. 6. 
Carapace somewhat rhomboid-ovate; width a little less than one-half 
the length : posterior articulating margin less than half the greatest 
width in the middle. From the postero-basal margin the outline is 
gently curved downwards for about three-sevenths of the length, and 
then turns more abruptly upwards and forwards, the anterior end ter¬ 
minating in an acuminate process. Posterior and basal margins marked 
by a narrow raised border. Dorsal margin very slightly curved for 
three-fourths the length, the anterior fourth being more abruptly bent 
downwards to the pointed extremity. 
Surface somewhat strongly striated concentrically. 
This species differs in having a proportionally greater width than the preceding. 
Fig. 6. The left valve of the carapace of this species. 
Geological position and locality. In the Waterlime group, near Buffalo. 
Ceratiocaiis : sp.? 
Plate LXXXIY. Fig. 7. 
The figure represents a crushed specimen, which preserves the mutilated carapace 
and several of the articulations, but too indistinct to be determined : it may be 
identical with the preceding. 
Plate LXXX A. Fig. 10. 
Last joint of the abdomen or tail thick and rounded : the larger tail- 
spine rounded, very strong at the base, and grooved for the reception 
of the smaller spines. 
This specimen is associated with some fragments of the posterior joints, in the 
same rock with Eurypterus remipes. It differs from the preceding species in being 
larger at base, and strongly grooved : the fragments of the crust associated with it 
are strongly striated. 
