12 



PLATE V. 



spicula of the lining membrane of the cloaca. X 130 

 linear. 



LEUCONIA FISTULOSA, Bowerlank. 



Vol. ii, p. 39, ' Mon. Brit. Spongiadse.' 



Fig. 9. A specimen of L. fistulosa from Plymouth. 

 Natural size. Dried specimen. 



Figs. 10, 11. Two specimens of L. fistulosa from off 

 Saints' Bay, Guernsey. Natural size. Dredged by 

 the Rev. A. M. Norman. From dried specimens. 



Fig. 12. One of the large fusiformi-acerate, ex- 

 ternal, defensive spicula. X 80 linear. 



Fig. 13. An equiangular, triradiate, skeleton spicu- 

 lum of the normal form. X 123 linear. 



Fig. 14. An equiangular, triradiate, skeleton spicu- 

 lum of an abnormal form. X 123 linear. The elonga- 

 tion of the third ray is variable, and usually in the 

 direction of the long axis of the sponge. 



Fig- 15.' One of the spiculated, equiangular, tri- 

 radiate, internal, defensive spicula. X 123 linear. The 

 spicular ray is in the downward direction. 



Fig. 16. One of the slender, rectangulated, triradiate 

 spicula. X 123 linear, from near the mouth of the 

 cloacal cavity. 



