10 



BRITISH SPONGIADiE. 



Genus XXI. — Halichondbia. 

 Section *.— Skeleton spicula acerate. 

 Sub-section A. — Dermal membrane aspiculous. 

 1. Halichondria Maclntoshii. | 2. Halichondria regularis. 



Subsection B. — Spicula of dermal membrane dispersed. 



3. Halichondria caduca. 



4. „ inconspicua. 



5. „ incerta. 



6. Halichondria coalita. 



7. „ mntula. 



8. „ cylindraoea. 



Subsection 0. — Spicula of dermal membrane reticulated. 



Section **. — Skeleton spicula acuate. 

 Subsection A. — Skeleton spicula smooth. Dermal spicula dispersed. 



19. Halichondria Thompsoni. 



20. „ forceps. 



21. „ simplex. 



22. Halichondria subdola. 



23. „ foliatii. 



Subsection B. — Skeleton spicula smooth. Dermis reticulated. 



24. Halichondria corrugata. 



25. „ falcula. 



26. Halichondria flabellifera. 



Section ***. — Skeleton spicula spinous- acuate. Dermal spicula more 

 or less fasciculated. 



Subsection A. — Spicula of dermal membrane fasciculated. 



2'1(. Halichondria incrustans. 34. Halichondria scandens. 



35. ,, Batei. 



36. „ nigricans. 



37. „ albula. 



38. „ expansa. 



39. „ virgea. 



