Explanation of Plate I. 



The figures were drawn from nature by A. H. Verrill. 

 Fig. 1. Ophioplus tuberculosus (Lym.) Ver. Dorsal surface. X 8. 



Fig. la. The same. Side view of several joints from the middle 

 portion of an arm. X 8. 



Fig. lb. The same. Distal part of an arm, dorsal view. X 8. 



Fig. 2. Ophiacantha (Ophialctsa) nutHngWVer. Side view of a por- 

 tion of an arm, near the base, showing- three rows of spines. 



Fig. 3. Ophiomusium stellatumVer. Dorsal view of a part of the 

 disk and base of an arm. X 8. 



Fig. 3(7. The same specimen. Ventral view. X 8. 



