204 PALAEONTOLOGY OF NEW YORK. 



elevated grooved line runs backward, bifurcating once anil becoming extinct 

 before reaching the middle of the shield. 



The eyes arc wanting, but the sockets of the ocular peduncles are plainly 

 discerned. The antennules are absent, the antennae being represented by 

 two very long and large joints, which are flat on their lower surface, convex 

 above and somewhat inflated in the middle; their inner extremities are 

 concealed beneath the cephalothonix, but they are undoubtedly the distal 

 peduncular joints of these appendages similar to those in some species of 

 Crangon (C. boreas). A single joint of a maxillary palpus (?) is visible on the 

 right side of the specimen, followed by portions of all the five pairs of 

 ambulatory appendages. Of the first leg two joints are visible, the proximal 

 being very broad where it disappears beneath the carapace, tapering to a 

 narrow anterior extremity ; the distal joint is also broad, but narrower than 

 the former; the second leg is indistinctly represented by fragments of two 

 joints, both of which appear to have been slender; the third leg shows two 

 joints, the proximal broad and the distal more slender; the fourth is repre- 

 sented by a single slender inner joint, while the fifth shows three joints, all of 

 which are very slender. 



The abdomen tapers rapidly toward the telson, the somites increasing in length 

 as they grow narrower. The somites are strongly arched, the ventrolateral 

 portions being somewhat incurved and posteriorly inclined. The basal joint 

 of the first two abdominal appendages on the right side, and of the second 

 and third pair on the left side are visible. The surface of the somite, 

 though indistinctly preserved, was evidently ornamented as in the 

 cephalothonix. 



The telson consists of a broad, rapidly tapering, convex spine, bearing a low 

 axial ridge ; articulated to its anterolateral margins and to the posterior mar- 

 gin of the ultimate somite are the compound lateral spines, which are con- 

 nected by a membranous expansion. The lateral caudal spines are com- 

 posed ol a shorl basal joint, sub-pentagonal in outline, the anterior margin of 

 which is articulated to the ultimate somite, the outer posterior margin being 



