101 



PLATE XLI. 



HALICHONDEIA GLABEA, Bowerbank. 



Vol. ii, p. 232, ' Mon. Brit. Spongiadse.' 



Fig. 1. A specimen of the species from Scar- 

 borough. Natural size, the lighter and upper por- 

 tion of the figure representing the sponge. 



Fig. 2. A fully-developed skeleton spiculum. X 

 250 linear. 



Fig. 3. An immature skeleton spiculum. X 250 

 linear. Intermediate sizes between figs. 2 and 3 are of 

 frequent occurrence. 



HALICHONDEIA ANGULATA, Bmoerbank. 



Vol. ii, p. 233, ' Mon. Brit. Spongiadae.' 



Fig. 4. Represents the type-specimen from 

 Guernsey in the cabinet of the Rev. A. M. Norman. 

 Natural size. 



Fig. 5. A small piece of the dermal membrane, 

 exhibiting the structure of its unispiculous network. 

 X 80 linear. 



Fig. 6. Oue of the skeleton spicula. X 250 

 linear. 



Fig. 7. A small and slender acerate, tension spi- 

 culum. X 250 linear. 



Fig. 8. One of the subangulated, tricurvate 

 acerate, tension spicula. X 530 linear. 



HALICHONDEIA CADITCA, Bowerbanlc. 



Vol. ii, p. 234, ' Mon. Brit. Spongiadse.' 



Fig. 9. Represents the type-specimen from the 

 northern side of St. Catherine's rock, at Tenby, in the 

 dried state. Natural size. 



Fig. 10. Represents two larger and more fully 

 developed specimens preserved in spirit from Guernsey. 

 In the cabinet of the Rev. A. M. Norman. Natural 



