. Dwellers of the sea and shore . hydractinia; a colony of tubularian iiydroids. (photograph made of the living animals growing on a shell occupied by a hermit crab; greatly enlarged.) markable instance known as commensalism, a term which, freely defined, means "dining at the same ; But in this case, as indeed is the case with most true commensal animals, they do more than merely dine together; they really render each other a service. That is to say, this sort of association is formed for mutual benefit. The tubularians, beside the concealment they

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Keywords: ., bookcentury1900, bookpublishernewyorkt, booksubjectmarineanimals