268 



EDWARD S. MORSE. 



touched with white. Even the base of the foot behind has a 

 small blotch of white showing only when the foot is greatly 

 elongated. This coloration in all exposed parts of this region is 

 certainly a curious feature. It is as sharply defined and localized 

 as if one with a paint brush had delicately touched with white 

 every exposed part of the animal within this limited area. It is 

 true the external shell is also touched with white at the anterior 

 end. In the young a dot of white is seen in the first three or 

 four transparent interspaces of the free periosteum. In older 

 specimens these white spots are drawn out in broken lines; not 

 in all specimens, however. In older specimens anteriorly the 



FIG. 5. FIG. 6. 



FIG. 5. Glands from side of pedal opening. 

 FIG. 6. Glands from anterior mantle margin. 



whitening is sometimes seen on the dorsal side of each rib. 

 This peculiar coloration is apparently correlated with the attitude 

 of the animal in nature. Resting on its back the ventral region 

 of the animal shows this whitening. Are the white markings at 

 the anterior end of the shell another indication that the creature 

 more often or habitually buries itself siphonal end downward? 



Along the anterior half of the mantle, as it springs from the 

 edge of the periosteum, are seen a number of what appear to be 

 short white lines with glandular enlargements. They begin a 

 little in advance of where the mantle parts, forming the pedal 

 orifice, and are separated by a considerable space (Fig. 5), 

 becoming crowded toward the rounded anterior border (Fig. 6). 

 They spring from just under the edge of the v periosteum and 



