- Entosternum, entosternite or plastron of Limulus Polyphemus, Latr.
N.S.), and in a series of subsequent memoirs, in which the structure of the entosternum, of the coxal glands, of the eyes, of the veno-pericardiac muscles, of the respiratory lamellae, and of other parts, was for the first time described, and in which the new facts discovered were shown uniformly to support the hypothesis that Limulus is an Arachnid.
- Ventral surface of the entosternum of Limulus Polyphemus, Latr.
- Ventral surface of the same central and the lateral eyes entosternum as that drawn in fig.
- Entosternum of scorpion (Palamnaeus indus, de Geer); dorsal surface.