PLATE II. 



Figs. 1-3. Transverse sections of tlie thorax of Ceraurus pleurexaiithemus. Enlarged 

 to three diameters. 

 s. Dorsal shell. 



b, b. BranchiiB. 



4, 4. Thoracic legs. 



a, Fig. 2. Basal joint of the leg, L. 



0, Fig. 3. Transverse section of the basal joint. 

 Fig. 4. Transverse section of the pygidium of the same species. Enlarged to 

 three diameters. 



s. Dorsal shell. 



s". Section of one of the spines of the pygidium. 



h. Base of the other spine of the jiygidium. 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. 



s. Dorsal shell. 



c. Cephalic cavity. 

 4, 4. Thoracic legs. 



Figs. 6, 8. Longitudinal sections of Ceraurus pleurexanthemus. Enlarged to three 

 diameters. 



s. Dorsal shell. 



V. Visceral cavity. 



4, 4. Fragments of thoracic legs. 



0, Fig. 6. Basal portion of one of the same. 



X, Fig. 8. Legs attached to the pygidium. 

 Fig. 9. Transverse section of the thorax of Asaphiis j^latycephalus. 



s. Dorsal shell. 



4. Basal joint of a thoracic leg. 

 Fig. 10. Transverse section of an enrolled CaZi/mc7ic sc?iam. Enlarged to three 

 diameters. 



s. Dorsal shell. 



h. Hypostoma. 



c. Cephalic cavity. 



V. Visceral cavity. 



4, 4. Sections of the thoracic legs. 



