104 BRITISH SPONGIADJ). 



" The singularity of the skeleton structures and the 

 beautiful dermal rete of this species renders its dis- 

 crimination by no means a difl&cult task." 



18. Halichondeia coealloides, Bow., n. sp., iv, Plate 

 VII, figs. 1—3. 



" Sponge ramous dichotomously, surface slightly 

 rugose. Oscula simple, dispersed. Pores inconspi- 

 cuous. Dermal membrane abundantly spiculous, reti- 

 culated ; rete more or less fasciculated, fasciculi irre- 

 gularly disposed ; areas small, very irregular in form ; 

 spicula acerate, long, more or less variable in dia- 

 meter, same form and size as those of the skeleton. 

 Skeleton — rete irregular, diffused ; interstitial and 

 intermarginal cavities very large ; spicula acerate, long 

 and rather stout. 



" Colour. — In the dried state, light fawn-yellow. 



" Habitat— TAth of Forth ; Mr. D. Eobertson. 



" Examined. — In the dried state. 



" I received this sponge from my friend the Rev. A. 

 M. Norman, to whom it was presented by Mr. D. 

 Robertson. Its external appearance in the dried state 

 is very like that of a small branching coral or a Gor- 

 gonia. The surfaces of the branches are all more or 

 less rugose or papulous ; they are all cylindrical, gradu- 

 ally attenuating to their distal terminations. There 

 are a few comparatively large oscula rather exceeding a 

 line in diameter, but by far the greater number of 

 them are minute ; they are irregularly dispersed on all 

 parts of the branches, and are rather numerous. The 



