5a 



PLATE XXI. 



DicTTOOYLiNDEus PUJiiLus, Bowerhank. 



Vol. ii, p. 114, ' Mon. Brit. Spongiadaa.' 



See pi. XIX, fig. 19, vol. iii, for a representation of 

 tlie sponge. In consequence of tlie great number of 

 the spicula required to illustrate the other three species 

 represented in that plate, those belonging to D. 

 pumilus were forced to be given in another plate. 



Fig. 1. — A large, acuate, skeleton spiculum from the 

 axis of one of the columns. X 80 linear. 



Fig. 2. — The basal portion of a spinulate skeleton 

 spiculum. X 80 linear. 



Fig. 3. — A slender, acerate, tension spiculum. X 80 

 linear. 



Fig. 4. — One of the internal defensive spicula. X 250 

 linear. 



DiCTYOcrLiNDKus ACULEATUS, Bov:erhaiilc. 



Vol. ii, p. 109, ' Mon. Brit. SpongiadEe.' 



Figs. 5, 6. — Ptepresent specimens dredged off Scar- 

 borough by Mr. Bean. 



Fig. 7. — A larger and more fully-developed specimen 

 of I), aculeutus dredged off the Xorthnmberland coast 

 by Mr. Albany Hancock, to whom I am indebted for 

 this very illustrative specimen. This sponge was 

 soaked in water for some hours before it was drawn, 

 to restore it as nearly as possible to the condition in 

 w^hich it was when in the living state. Xatural size. 

 The spicula of this species are from the type-specimen 

 of the species presented to me by my late highly- 

 esteemed friend Mr. Bean, of Scarborough. 



