THE ORANGE STRIPED ANEMONE. 365 



means of a mirror placed at the bottom of the pool), the body 

 outline becomes almost impossible to trace. Another aid to 

 concealment is afforded by the immobility of the tentacles when 

 the animal is fully expanded, and also by the extreme deliberation 

 with which the act of expansion takes place. When contracted 

 (Fig. 2) the animal appears like a small dark greenish button- 

 like protuberance, whose outline, however, is interrupted 'by the 

 orange stripes. This combination of dark olive green and 

 orange (which seems at first a rather gaudy ensemble) can be 

 shown to be a peculiarly effectual one for the type of rock on 

 which Sagartia is usually found seated, i.e., the granites of the 

 New England coast. The rock is flecked with black, and with 

 varying tints and shades of gray, green, reddish, and yellow, 

 from the included quartz, feldspars, hornelende, etc., and from 

 the various chemical combinations with these minerals which 

 the oxygen of the air and the substances of the sea water make. 



Sagartia lucice occurs below tide level on piles, or other sub- 

 merged objects, and is frequently associated with the rock 

 barnacle (Balanus balanoides), and with two species of mussels; 

 the ribbed mussel (Modiola plicatula), and the black or edible 

 mussel (Mytilus edulis}. In the same company may also be 

 found small clusters of the common oyster (Ostrea virginica). 

 More often, however, the habitat of Sagartia are the tidal pools 

 between the tide lines, among rocky headlands and shores, and 

 rocky tidal islands, in which the New England coast abounds. 

 Wherever it occurs, however, it will usually be found attached 

 to vertical, or overhanging surfaces, rather than to horizontal 

 ones (Fig. 3). In some few tidal pools it was found, however, 

 on the gently sloping sides. Comparatively few enemies, either 

 organic or inorganic, attack those individuals which are attached 

 to the vertical or overhanging sides of the pool, while those that 

 becomes detached and cast to the bottom are soon either buried 

 by debris brought in by wave or tidal currents, or fall an easy 

 prey to mud crabs (Panopeus}, rock crabs (Cancer irroratus), or 

 hermit crabs (Eupagurus longicarpus] , for Sagartia, despite its 

 armament of nettling acontia, is without means of defense 

 against these heavily armored scavengers. 



As a rule, the rock itself seems to be the favorite location of 



