51 



PLATE XX. 



DIOTTOCYLINDRUS HUGOS us, Bowerbank. 



Yol. ii, p. 119, ' Mon. Brit. Spongiadse.' 



Fig. 1. Represents an average-sized specimen in 

 the condition in which it came from the sea at Shet- 

 land, having been preserved in spirit. Natural size. 



The specimen figured is larger than the greater 

 number of the species that I have in my collection. 

 The largest I have seen is in the cabinet of the Rev. 

 A. M. Norman. When dried this species appears very 

 coarsely hispid. 



Fig. 2. One of the flexuous cylindrical spicula from 

 the axial column of the sponge. X 80 linear. 



Fig. 3. One of the acerate spicula of the skeleton. 

 X 80 linear. These spicula vary considerably in form, 

 many of them being sub-fusiform or inequi-acerate. 



Fig. 4. An external, defensive, acuate spiculum 

 from the termination of one of the radial fasciculi. 



DICTYOCYLINDEUS EADiosus, Bowerbank. 



Yol. ii, p. 105, ' Mon. Brit. Spongiadse.' 



Fig. 5. Represents the sponge in its dried state. 

 Natural size. 



Fig. 6. One of the acuate skeleton spicula from the 

 axial column of the sponge. This figure also represents 

 the external defensive spicula, the only difference being 

 that they slightly exceed those of the axial column in 

 size. X 80 linear. 



Fig. 7. An acerate skeleton spiculum from the axial 

 column. They are usually rather more slender in their 



