164 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
ined at night thinking that they might be nocturnal in their 
habits. In A. castanea the foot is broad and short and extends 
from the ventral middle line of the shell. The anal syphon, 
showing only the valve, projects slightly beyond the edge of the 
shell ; it is very broad at its base, the opening large but represent- 
ing an irregular outline from the extreme tenuity of its walls. 
The branchial opening is fringed with fifteen papillae, a few 
bifurcated. The color of the animal is reddish yellow. 
ASTARTE SULCATA Fleming. 
Fig. 2L Length, 31 mm. 
As in the other Astartes three or four days elapsed before 
the slightest opening of the shell was observed and after expand- 
ing, the slightest vibration of the table by footsteps on the floor 
caused the shell to close. The anal syphon is short, the only 
Fig. 21. — Astarte sulcata Fleming. 
part exposed being the valve which was more prominent than in 
A. castanea. Its walls were of extreme tenuity. Below, a dozen 
or more papillae marked the branchial opening. The color was 
reddish orange. The foot did not protrude in this species. 
ASTARTE CREBRICOSTATA Forbes. 
Fig. 22. Length, 29 mm. 
In timidity and behavior precisely like the other species 
herein described. The anal syphon showing only the valve is 
slightly smaller at its base than in the preceding species; it 
projects a little farther and the walls being thicker, the symmetry 
