Van Name. — Simple Ascidians. 
PLATE 44. 
Fig. 5. Bostrichobranchus pilularis (Verrill). Camera-lucida drawing of part 
of the branchial sac of an individual of moderate size from Casco 
Bay, Maine. X 38. 
Fig. 6. Bostrichobranchus pilularis (Verrill). One field of the branchial sac 
of a very large individual from off Race Point, Massachusetts. 
X23. 
