EXPLANATION OF PLATES.
PPP. 21
Fig. 12. | A fragment of shale preserving the remains of fifteen young individuals, nine of which are to be seen on the side represented in the figure. Chemung group ; Warren, Pa. |
Echinaris Punctata, Hall. | |
Page 6. | |
Fig 13. | A nearly entire individual showing the form and relation of the parts, and the number of naked abdominal segments. |
" 14. | An enrolled specimen, with the valves partially opened and the abdomen extended along the ventrum. The specimen shows in a very satisfactory manner the optic spots, the number and distribution of the nodes, and the limits of the cephalic region. |
" 15. | id. Lateral view, showing the position of the abdomen in this example. The specimen is flattened, and does not represent the normal convexity of the valves. |
" 16. | The ventral side of zu. specimen preserving the mandibles in situ. Hamilton group ; New York. |
PLATE II. | |
Elymocaris siliqua,Beecher. | |
Page 13. | |
Fig 1. | A specimen wanting the anterior portion of the carpace, but preserving the abdomen and telson, with its appendages. |
" 2. | The carnpace with the valves sepearted, showing their form with the rounded elevations and optic nodes on the Cephalic portion. Chemung group ; Warren, Pa. |