182 BRITISH SPONGIAD^B. 



early stage of its development, in truth, a mere pellicle 

 of the structures. 



" The occurrence of this singular mixture of species 

 affords a valuable lesson to students of the Spongiadse, 

 as the occurrence of one species in a very young con- 

 dition in small patches upon, or nearly enveloping, 

 another is by no means an unusual occurrence among 

 both British and Foreign species. 



" I received another specimen of Raphiodesma lingua, 

 dredged at Westport Bay in four fathoms by the Rev. 

 Mr. Norman, which varied greatly from the usual and 

 normal form of the sponge so as to render it very 

 difficult of recognition by its external characters. It 

 completely coated the gibbous valve of a Pecten oper- 

 cularis for about a quarter of an inch in thickness, and 

 the surface of the sponge was very much more rugged 

 than is usual in this species." 



12. DESMACIDON COLUMELLA, Bow., in, 243, PI. 

 LXXVIII, figs. 68. 



Genus 26. RAPHYRUS, Bow, i, 201 ; n, 10. 



RAPHYRUS GRIFFITHSII, Bow., n, 354, i, PL XIII, fig. 

 265 ; in, PI. LXIV. 



1862 Papillinasuberea, Schmidt. Spong. Adriat., p. 69. 

 1868 Rapliyrus GriffitTisii, Parfitt. Sponges of Devonshire 



(Trans. Devon. Assoc. Lit. Soc. and Art), p. 9 (separate 



copy). 

 1870 Papillina suberea, Schmidt. Spong. Atlant., p. 77. 



Very fine masses of this interesting sponge are 



