197 



PLATE LXXIII. 



Halichondeia foliata, BowerbanJc. 



Fig. 1. — Represents tlie finest and best-developed 

 specimen from Shetland in tlie condition in whicli it 

 came from the sea. Natural size. 



Fig. 2. — Is from a small, but well-develoj^ed speci- 

 men from Scarborough in the dried state. Natural 

 size. 



Fig. 3. — One of the slender, acuate, tension spicula 

 from the dermal membrane. X 250 linear. 



Fig. 4. — A skeleton spiculum. X 250 linear. 



Fig. 5. — One of the tricurvate-acerate, tension 

 spicula from the interstitial membranes, X 250 

 linear. 



Halichondeia edusa, Botverhanl: 



Fig. 6. — Represents the type-specimen of the species 

 in the wet condition. In the cabinet of the Rev. A. 

 M. Norman. Natural size. 



Fig. 7. — A small portion of the dense polyspiculous, 

 dermal reticulation. X 180 linear. 



Fig. 8. — An acerate skeleton spiculum. X 250 

 linear. 



Fig. 9. — A tension spiculum from the interstitial 

 membranes. X 250 linear. 



Halichondeia eegulaeis, Bowerhank. 



j^io-. 10. — Represents the type-specimen from Sark. 

 Natural size. 



Y\cf. 11. — One of the skeleton spicula. x 250 



linear. 



