[■LATE XIX. 49 



defensive spicula. X 80 linear. These spicula are 

 exceedingly numerous. 



Fig. 17. — An average-sized, subclavated, internal, 

 defensive spiculum. X 150 linear. 



Fig. 18. — One of the large-sized, internal, defensive 

 spicula, profusely but minutely spinous. X 150 

 linear. 



DiCTYOCYLiNDRUs TUMiLus, Boverhcmk. 



Vol. ii, p. 114, ' Mon. Bvit. Spoiigiaito.' 



Fig. 19. — Represents the specimen I obtained at 

 Tenby. Natural size ; dried state. The stone on 

 which the specimen is based is larger than represented 

 in the figure. 



For the spicula of this species see Plate XXI, figs. 

 1, 2, 3, and 4. 



