44 



ixvei;tebi;ate animals. 



sponge-colony, comprised of innnraeraljle liorny fibres interlaced 

 into a continuous network, in such a way as to leave innumeraljle 

 h'.le:, and canals between its bundles. In the living condition, the 



Fi,^ 21. — Stnictiue "t S|ioji^i.l;L A, VLTtical section of the outer layer of HaJi- 

 sorrrn hhiilari^, a Siioiigi^ i]i wljicli the skeleton is wanting, enlarged 7.5 times 

 (after F. E Scliultze) ; 3' j' " Pores," or openings of inhalant canals by which water 

 is conducted to tlie ciliated clianiliers (a a) ; e Commencement of a larger exhal- 

 ant canal, cniiductiiig from tiic ciliated chambers to the deeper canals, by which 

 the watrr is Iliially carriril o:l' U\ lie cxpelted from the "oscula"; fir (/ Young stages 

 of tlie rc].rodiicl i\i. liiniii.^ m' s|iores. B, Part of a single ciliated chanllicr of tlie 

 saini: sponge, I r;uis\'iisrly diviilr.l, anrl enlarged 800 diameters (after Saville Kent). 

 showing t!ie il.igrllati' (■(■lis or " sjiouge. particles," witlr their inw.ardly direeltd 



lla:,'el'a. C, A single llagcl al ■ll ofllie same, slill further enlarged: / Khigellum ; 



■M CAVav r.iuiid the liase of I lie llagrlliuii ; V, ,\iielriis; c Cuntraetile vesicle. 



wliole of tilis skclcLon ii i.-ii\'ercd f.\tL'i-ii:illy and internally with 

 a, soft ]iiotii|ilasmic ni^iterial, wliicli h,-is been often termed the 

 " s|iii)io-,. . lly,^],^" as it represents the soft ])arts of the sponge. 

 l'j.\aiiiiijid niciosro|iically, the " sponge-llesh " is found to be com- 



IJO.sc I of 



inoinioui immbfr of minut'j protoplasmic bodies or 



