Vig. 
PLATE 64. 
i 296. 1. PuatTynorus TRENTONENSIS. ( Pag. 235.) 
1 a, b. Portions of the buckler and caudal shield of this species. 
1c. A fragment of the buckler, more compressed than the preceding. 
id. A magnified portion of the crust, showing the pustules upon the surface. 
le. This figure is from a plaster cast of a specimen from the Blue limestone of Ohio. 
Fig. 2. 297. 2. CaLYMENE BECKII. (Pag. 237.) 
2a. An imperfect specimen, preserving the thorax and caudal shield, and the left maxillary portion of the 
buckler. 
2b. A perfect specimen, with the exception of the maxillary portions, which are separated at the facial suture. 
2c. A similar specimen, preserving the maxillary parts, which give a different outline to the cephalic shield. 
2d. Part ofa single articulation enlarged, showing the spine upon the centre, with papillose surface. 
2e. A portion of the surface of the buckler enlarged, showing the papillose character of the surface. 
Fig. 3. 298. 3. CaALYMENE SENARIA. (Pag. 238.) 
3a. A large specimen from the Trenton limestone, with the buckler abruptly curved downward in front. 
3b. A small specimen from the same rock. 3 ec. Lateral view of the same. 
3 d. A small specimen from the Hudson-river group. 
3 e, f, g. Three views of a contracted specimen from the Blue limestone of Ohio. 
3h. Lateral view of the eye of this species, enlarged. The eye is obtusely conical, with a depression or cavity 
at the apex, which is granulated as shown in 3 4. From the oblique conical form, this depression opens 
outwards and upwards, being protected on all sides by a thick crust. 
3k. The buckler of this species separated at the facial sutures, showing the form of the maxillary portions 
Y Y, which embrace more than half the oculiform tubercle. 
3 1. Front view of the buckler, showing the termination of the facial sutures. ” is the labrum, which occu- 
pies this position beneath the buckler. 
3m. The same enlarged, showing the lines of the frontal suture, and the termination of the facial sutures. 
3 n. The inside of the giabella, having the maxillary and basal portions separated. 
Big, 4. 299. 1. AcIDASPIS TRENTONENSIS. (Pag. 240.) 
4a. Front view of the specimen, which is folded (natural size). 
4 6. The same enlarged, to show more distinctly this part of the fossil. 
4c. Dorsal view (natural size). 4d. The same enlarged. 
4 e. The caudal extremity and part of the thorax enlarged. 
4 f. Margin of the maxille enlarged. 
Wig. 5. 300. 2. ACIDASPIS SPINIGER. (Pag. 241.) 
Fic. 6. 305. 2. Puacops? LAricAubus. (Pag. 248.) 
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