U. S. NATIONAL MUSEUM BULLETIN 100, VOL. 14, PART 1 PLATE 1 
1, Valve of large, involute, tridentate pedicellaria of draeosoma coriaceum (A. Agassiz). 
AR 
2, Valve of large, involute, tridentate pedicellaria of Aracosoma owstont var. nudum Mor- 
tensen. Hybrid (?). x 33. 
3, Large, involute, tridentate pedicellaria of Aracosoma owstoni var. nudum Mortensen 
Hybrid (2). X 17. 
