422 REVISION OP THE MONAXONID SPONGES, iii 



Fig. 18. — Raspailia tenella. a, Principal spicules; styli and subtylostyli. 

 a', Basal ends of principal spicules. 6,Acantho8tyli. c, Auxiliary oxea 

 and styli; c',the same, drawn to a larger scale. 



