WATERLIME GROUP. 
405 * 
are very thick and strong, and the joints comparatively short, having 
their origin at about the anterior third of the carapace. Postoral plate 
lyrate, with the anterior cordiform. Maxillary plates rhomboidal, more 
than one-half longer than wide ; the inner anterior extremities ex¬ 
tending beyond the postoral plate, and distinctly serrate. Second joint 
strong and wide; third joint very short; fourth joint about twice as 
long as wide ; fifth and sixth joints nearly one-fourth longer than wide ; 
seventh and eighth comparatively short, as wide as long; the fixed 
chela very small. The terminal palette is excessively large, ovate, 
longer than the preceding joint, and nearly as wide. The thoracic 
appendage is articulated to the first thoracic articulation in the usual 
manner : the lower margin of the first joint adjacent to this organ is 
prolonged in triangular extensions over the next joint; the appendage 
itself extends to the fifth joint of the body, and is imperfect at the 
extremity. 
Crust very thin. No scale-like markings have been observed, nor rows of 
scale-like pustules along the dorsal side. 
The simple chelate appendages or spines of the anterior feet are re¬ 
markably thick and strong, and were apparently more numerous than in 
the other species. The extensions or anterior edges of the last joints of 
the swimming feet are very strongly serrate. 
This species is distinguished by its robust elongate body, the long straight-sided 
carapace, very anterior eyes, strong and thick-jointed anterior feet, and extremely 
long swimming feet, with the great development of the terminal palette, and the 
little dilatation of the two preceding joints. The form of the postoral plate is very 
remarkable, though its posterior termination is unknown : the appendage is more 
prolonged and of a different form, and the adjacent articulation is very peculiar; 
and there are distinctive features in the maxillary plates. 
A single specimen only has been seen. 
Plate lxxxixx, fig. 1. The dorsal side of the specimen, preserving ten joints and a part 
of the eleventh joint of the body. 
Plate lxxxiii a, fig. 1. The ventral side of the specimen as it lies on the surface of the 
stone. 
Geological •position and locality. In the Waterlime group near Buffalo. 
