366 LEON AUGUSTUS HAUSMAN. 



Sagartia, for the creature can detach itself, at will, from its seat, 

 and move by mearis of its tentacles, or float about, head down- 

 ward, from the surface film of the water until a more favorable 

 locality is found. The fact that the rock, or other seat of equal 

 solidarity, is chosen more often than any other for the obsession 

 of Sagartia would seem to indicate that the creature possesses a 

 sense which instructs it regarding the relative stability of sub- 

 merged objects. However it is often found attached to the 

 shells of living mussels and even sometimes upon eel grass, fucus, 

 or other algae. It often occurs, also, attached to shells, and other 

 objects that have become firmly wedged into crevices in the rock 

 by the action of the waves. 



Sagartia is ordinarily solitary in its habit, and not communal, 

 and yet, what seem to be in effect, colonies, at least in so far 

 as mere physical propinquity is concerned, were met with in tidal 

 pools, where, apparently by repeated divisions, coupled with but 

 little migration on the part of the increasingly numerous progeny, 

 groups of from ten to twenty-five individuals, with their bases 

 almost in contact, were formed. That this group formation 

 aided in securing food was seen when large beach fleas (Orchestia 

 agilis), which were easily able to escape the embrace of a single 

 anemone, were at once, caught and held by the numerous 

 tentacles brought to bear in the capture by several contiguous 

 individuals at once, and easily nettled into a state of helpless- 

 ness. Possibly such a colonial existence (if it may be so called) 

 makes also for the more effectual protection of the individual 

 members of such a community. Such groupings seemed to be 

 the exceptions, and not the rule, in the disposition of the anemones 

 in the tidal pools. It is interesting to conjecture, that possibly 

 this grouping, perchance accidental at first, marks the beginning 

 of the development of a movement toward communal living on 

 the part of Sagartia. If this manner of living does make for the 

 better protection of the members of colony, and aids in securing 

 more frequent and larger captures of food, then we may suppose 

 that the collective individual will thrive at the expense of the 

 independent one, a law of progress derivable from other fields 

 also than the biologic one. 



The food of Sagartia consists mainly of small Crustacea, 



