49«» PALiEONTOLOGY OF NEW- YORK. 



Ceratiocai'is acuiiiiiiatus ( n. s.)- 



Platb LXXXIV. Fia. 6. 



Carapacb somewhat rhomboid-ovate; width a little lesa 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. 



Ceratiocaris : sp.? 



Plate LXXXIV. 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. 



Ceratiocaris aculeatus (n.s). 



Plate LXXX A. Fio. 10. 



Last joint of the abdomen or tail thick and rounded : the larger tail- 



epine 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. 



