The porifera and coelentera . e seen inmfts»i^e forms, such as ITttJ^HMytti or Trntori ? . whtre tli. separate individuals are quite indistinguisl.^ r. sri^. s^. only indicatevl by the c*scula In such case* the vVUii>osiie iudi\the sp^>n^ can scarv*ly be r«cv>^:msed: it becomes simply .growth in which the repetition of a number of similar and cv>mpie^phT«iolv^ical systems alone marks the primitive individuals. Most of the sponges in which the loss of individuality is most SPONGES 2f marked are inhabitants of Bhallow water; or, if not, they areforms whose ncarcKt allifjs are to be f
The porifera and coelentera . e seen inmfts»i^e forms, such as ITttJ^HMytti or Trntori ? . whtre tli. separate individuals are quite indistinguisl.^ r. sri^. s^. only indicatevl by the c*scula In such case* the vVUii>osiie iudi\the sp^>n^ can scarv*ly be r«cv>^:msed: it becomes simply .growth in which the repetition of a number of similar and cv>mpie^phT«iolv^ical systems alone marks the primitive individuals. Most of the sponges in which the loss of individuality is most SPONGES 2f marked are inhabitants of Bhallow water; or, if not, they areforms whose ncarcKt allifjs are to be found along the shore, andwhose ancestors have probaljly migrated into dcep«;r water in com-|>arativ*;ly recent timers. In other words, the impersonal con-dition, aa it may be termed, seems to have been correlat^^d at itsfirst origin witfi life in a habitat where the sponge has \Ai contendwith, and to adapt itself to, the action of stresses and strains whichare always very variable and often very severe, and where the. HjiongUla Uiynutris, auct. (afterW<;ltri<;r). i- FlO. 34. Ch/dina ocubjJUi, Pall, half-natural «i»!.ote, (Mcula ; it, atalk. form of the sponge becomes of the greatest importance in thestruggle for existence. Hence the sponge colony as a whole takeson some characteristic mode of growth which may vary greatlyfrom species to species, or even in different specimens of the samespecies. In this way a great numh»er of different shapes and formsarise whicli are often extremely irregular and amorphous, but whichcan usually be classed under one of a series of typical the starting-point we may conveniently take a small com-pact sponge with numerous oscula—that is to say, a colony in which SPONGES the persons are indistinguishable except by the exhalant vents ofthe canal system. A compact sponge of this kind, if it grows more or less equallyin all directions, becomes simply massire (Fig. 39). It may, how-ever, grow very greatly in a horizontal dire
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