52 PJ.ATE XX. 



proportions, and more flexuous than tlie acuate ones. 

 X 80 linear. 



Fig. 8. — One of the very slender, acerate, tension 

 spicula from the dermal membrane. X 80 linear. 



Fig. 9. — An attenuato-acuate, entirely-spined, in- 

 ternal, defensive spiculum. X 250 linear. 



When I first examined this species of sponge I did 

 not detect this form of spiculum. They are very few 

 in number, and had I not subsequently detected two 

 of them in sitit I should have been inclined to have 

 attributed the presence of one of them in the spicula, 

 prepared by nitric acid and mounted in Canada balsam, 

 to an accidental occurrence. We must, therefore, add 

 to the specific description in vol. ii, p. 105, the following 

 description of them : 



Internal defensive spicula attenuato-acuate, entirely 

 spined, minute, very few in number. 



