PLATE 64. 



Pig. 1. 296. 1. Platynotus TRENTONENsis. ( Pag. 235.) 



1 a, b. Portions of the buckler and caudal shield of this species. 



1 e. A fragment of the buckler, more compressed than the preceding. 



I d. A magnified portion of the crust, showing the pustules upon the surface. 



1 e. This figure is from a plaster cast of a specimen from the Blue limestone of Ohio. 



Fig. ± 297. 2. Calymene beckh. (Pag. 237.) 



2 a. An imperfect specimen, preserving the thorax and caudal shield, and the left ma.xillary portion of the' 



buckler. 

 •i b. A perfect specimen, with the exception of the maxillary portions, which are separated at the facial suture. 

 2 c. A similar specimen, preserving the maxillary parts, which give a different outline to the cephalic shield. 

 2 d. Part of a single articulation enlarged, showing the spine upon the centre, with papillose surface. 



2 e. A portion of the surface of the buckler enlarged, showing the papUlose character of the surface. 



Fig. 3. 298. 3. Calymene senakia. ( Pag. 238.) 



3 a. A large specimen from tlie Trenton limestone, with the buckler abruptly curved downward in front. 

 3 fr. A small specimen from the same rock. 3 e. Lateral view of the same. 



3d. A small specimen from the Hudson-river group. 



3 e,/, g. Three views of a contracted specimen from the Blue limestone of Ohio. 



3 A. 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 t. From the oblique conical form, this depression opens 

 outwards and upwards, being protected on all sides by a tliick crust. 



3 k. The buckler of this species separated at the facial sutures, showing the form of the maxillary portions 

 7 y, which embrace more than half the oculiform tubercle. 



3 /. Front view of the buckler, showing the termination of the facial sutures. ^ is the labrum, which occu- 

 pies this position beneath the buckler. 



3 m. The same enlarged, showing the lines of the frontal suture, and the termination of the facial sutures. 



3 It. The inside of the glabella, having the maxillary and basal portions separated. 



Fig. 4. 299. 1. AciDASPis TRENTONENSIS. (Pag. 240.) 



4 a. Front view of the specimen, which is folded (natural size), 

 t b. The same enlarged, to show more distinctly this part of the fossil. 

 4 e. Dorsal view (natural size). 4 d. The same enlarged. 



4 e. The caudal extremity and part of the thorax enlarged. 

 4 /. Margin of the maxillae enlarged. 



Fig. 5. 300. 2. AciDASPis spinigeh. (Pag. 241.) 



Fig. 6. 305. 2. PuAcops? ijvticaudus. (Pag. 248.) 



