PLATE XXII. 



Page 

 Kg. 1. Phi/maplectia scitula,}i'mde. Natural size. From the interior of a flint from the 



Upper Chalk at Oare, Wiltshire. The specimen belongs to the Jermyn-Street 



Museum 89 



Fig. 1 a. The same. Portion of the surface of the interior of fig. 1, enlarged six times, 



showing open canals radiating from slightly elevated centres. 

 Fig. 1 b. The same. Portion of the exterior surface of fig. 1, enlarged thirty-two times, 



showing the spicular structure of the sponge-wall. The square on the left side 



of the figure represents its natural size. 

 Fig. 2. Rhopalospongia gregaria, Benett, sp. Two-thirds the natural size. From the 



Upper Green Sand at Warminster, Wiltshire 90 



Fig. 2 a. The same. A vertical section of another specimen from Warminster, showing 



traces of the radiating canals and concentric markings of growth. Natural 



size. 

 Fig. 2 b. The sam,e. A transverse section of 2 a. Natural size. 

 Fig. 2 c. The same. The spicular structure of the interior. Enlarged sixty-four times. 



Drawn from a transparent section by means of the camera lueida. 

 Fig. 3. Rhopalospongia obliqua, Hinde. Natural size. From the Upper Green Sand at 



Warminster 90 



Fi"-. 3 a. The same. A transverse section of fig. 3, showing the distribution of the canals. 



Natural size. 



