and Functions of the Sponge. 139 



Pig. 8. SiliciouSj single-pointed, straight, moniliform spiculum of 

 the Spongia moiiiley Gr. (See Edin. New Phil. Jour. vol. i. 

 p. 348.) 



Fig. 9. Silicious, single-pointed, curved, long spiculum of the 

 Spongia sanguinea, Gr. (See zoological notices at the end of 

 the present Number.) 



Fig. 10. Silicious, curved, short spiculum, obtuse at both ends, 

 of the Spongia fruticosa. (See Edin. New Phil. Jour. vol. i. 

 p. 350.) For the S. hispida the same form occurs, but more 

 than double this length. 



Fig. 11. Calcareous triradiate spiculum of the Spongia compressa. 

 (See Edin. New Phil. Jour. vol. i. p. 166.) 



Fig. 12. Calcareous, clavate, curved spiculum of the S. compressa. 

 (Ibid.) 



Fig. 13. Calcareous, straight, very minute spicula of the S. 

 compressa. (Ibid.) 



Fig. 14. Calcareous, triradiate, large spiculum of the Spongia 

 nivea. (Ibid. p. 168.) 



Fig. 15. Calcareous, quadriradiate, minute spiculum of the S. 

 nivea. (Ibid.) 



Fig. 16. Calcareous minute fragments of triradiate spicula of the 

 S. nivea. (Ibid.) 



Fig. 17. Calcareous triradiate slender spiculum of the Spongia 

 coronata. (Ibid. p. 170.) 



Fig. 18. Calcareous, single-pointed, slightly curved long spiculum 

 of the S, coronata. (Ibid.) 



Fig. 19. Horny tubular thick fibres of the Spongia Jlstularis. 

 (See Edin. Phil. Jour. vol. xiv. p. 339.) a. Amber-coloured 

 horny translucent parietes. b. Dark opaque granular matter 

 filling the central cavity. 



Fig. 20. Horny tubular thin fibres of the Spongia communis. 

 (Ibid.) a. Amber-coloured transparent parietes. b. Empty 

 central cavity. 



Fig. 21. Living Spongia papillaris under water, shewing its 

 mode of generation, &c. (See Edin. New Phil. Jour. vol. ii. 

 p. 133.) ttj a, Minute pores through which the currents enter. 

 b, Commencement of the internal canals, c. Uniting of the 

 internal canals to form a fecal orifice. d, A fecal orifice dis- 

 charging a current of water with feculent matter, e, A fecal 

 orifice discharging two ova and feculent matter with the cur- 

 rent. f,f, Groups of mature ova. g, Ovum passing into a 

 canal, h, Gelatinous base connecting this animal to the rocks. 



