PLATE II, 
Figs. 1-3, Transverse sections of the thorax of Ceraurus pleurexanthemus. Enlarged 
to three diameters, 
s. Dorsal shell. 
b, b. Branchiæ. 
4, 4. Thoracic legs. 
a, Fig. 2. Basal joint of the leg, L. 
0, Fig. 3. Transverse section of tho basal joint. 
Fig. 4. Transverse section of the pygidium of the same species. Enlarged to 
three diameters, 
s. Dorsal shell. 
8". Section of one of the spines of the pygidium. 
h. Base of the other spine of the pygidium. See Plate IV. fig. 5. 
x. Base of leg. 
4, 4. Sections of legs cut across. 
Figs.5, 7. Longitudinal sections of the anterior portion of Calymene senaria, En- 
larged to three diameters, 
$. Dorsal shell. 
c. Cephalic cavity. 
4, 4. "Thoracic legs. 
| Figs. 6,8. Longitudinal sections of Ceraurus pleurexanthemus. Enlarged to three 
diameters. 
8. Dorsal shell. 
v. Visceral cavity. 
4, 4. Fragments of thoracic legs. 
0, Fig. 6. Basal portion of one of the same. 
v, Fig. 8. Legs attached to the pygidium. 
Fig. 9. Transverse section of the thorax of Asaphus platycephalus. 
s. Dorsal shell. 
4. Basal joint of a thoracic leg. 
Fig. 10. Transverse section of an enrolled Calymene senaria. Enlarged to three 
| diameters. 
| s. Dorsal shell. 
h. Hypostoma. 
c. Cephalic cavity. 
v. Visceral cavity. 
4, 4. Sections of the thoracic legs, 
