281 



PLATE LXXXIV. 



DlCTYOOYLINDRUS EEOTANGTJLUS, 



Fig. 1 Represents the type-specimen in the cabinet 

 of the Rev. A. M. Norman of the natural size. The 

 detached piece near the top of the plate with the X at 

 its base is a continuation of the main stem of "the 

 sponge from the spot at the top indicated by a corre- 

 ponding mark. 



Fig. 2. One of the large acuate external defensive 

 spicula. X 80 linear. 



Fig. 3. One of the long and very slender acuate 

 tension spicula of the dermal membrane. X 80 

 linear. 



Fig. 4. An average-sized acuate spiculum from the 

 axial skeleton of the sponge ; occasionally they attain 

 the size of the external defensive ones represented by 

 figure 2. X 80 linear. 



Fig. 5. A cylindrical skeleton spiculum. X 80 

 linear. 



Fig. 6. Anacerate skeleton spiculum. X 80 linear. 

 The spicula represented by figures 5 and 6 are of com- 

 paratively rare occurrence. 



Fig. 7. One of the entirely spined, attenuate -acuate, 

 internal defensive spicula. X 250 linear. 



DICTYOOTLINDEUS RECTANGULUS, Bowerbank. 

 Plate LXXXIV. 



Sponge ramous, slender ; branches regularly cylin- 

 drical ; primary branches dividing dichotomously or 

 trichotomously ; secondary branches at right angles to 

 the primary ones ; surface hispid. External defensive 



