PLATE XXIII. 



Figs. 1-4. Arcturus studeri. 

 Fig. 1. Male, dorsal aspect. 

 Fig. 2. Male, lateral aspect. 

 Fig. 3. One of the anterior thoracic appendages. 

 Fig. 4. One of the posterior thoracic appendages. 



Figs. 5-8. Arcturus americanus. 

 Fig. 5. Dorsal view. 

 Fig. 6. Lateral view. 



Fig. 7. One of the anterior thoracic appendages. 

 Fig. 8. One of the posterior thoracic appendages. 



