ao SPOXGES 



A form resembling a cix-k'sHHWuK In the British sjHvies I^UittiuiiM 

 nifttu « sprt^juiing iH>lony is formoil, comjHXseii of mimorv>us tiattoiuvl 

 volcano-like individuals. 



In the cases wjioi-e the jKH'sons of the colony are not distinct 

 from one another, the colony as a whole may havo a form scaivoly 

 ditlVring tivm, or ovon identical with. th.Ht of the sjvui^' individual. 

 and in oxtivme c.-»ses the colony can only W distinijuishcd fi\nu thr 

 individuid by its lar^>r sire and greater number of oscula. lnstance> 

 of this aiv well seen in the genus Clothrina suuong Asci>ns, when 

 the full-gnnvu ivlony forms a spreading nuHss of tubes. Typically 

 the individn;Us aiv indicatevl in those forms by cone-like elevations 

 of the tuK^r system, each surmovuitoil by an osculum i^Kig. 7, Ci 

 di%thiHs\ In some sjHvies of the genus, however, the sjK>nge .assumes 

 a very compact form, like a cushion when sessile (Fig. 6, Ci 





rHicuInmX or more or less globul.-u- when stalkevi (^Fig. S. Ci htcufk^A 

 AXhl then the number of oscula alone indicates the number of 

 individujils^ In other cases, again, the tubes may ramify in ont 

 plane, fonning an incrusting colony spread o\"er stones or seaweeds, 

 frv>m which i^sculiir tubes arise at intervals, 



Iustaxtoe« of spouge colonies in which the form of the colony is mori. 

 or le<ss ivieutical with that of ihe individual are v*ry common als<> 

 •moQ^t siliceous and homy $poag««. The Kfist examples are seen in 

 mfts»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 vV'Uii>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 



