PLATE XXXVI. 



Tage 

 Pig. 1. Synopella pulvinaria, Goldf. sp. Natural size. Showing the upper surface of a 



specimen from the Lower Green Sand at Farringdon, Berkshire 190 



Fig. 2. Synopella Goldfussi, Hinde. Natural size. Showing the summit and a portion 

 of the lateral surface of a flattened specimen. From the Upper Chalk at 

 Maestricht 191 



Fig. 3. Oculospongia dilatata, Eoem. sp. Natural size. Showing the upper surface of 



an average specimen from the Lower Green Sand at Farringdon, Berkshire . . 192 



Fig. 4. Diaplectia auricula, Hinde. Showing the under surface of an ear-shaped indi- 

 vidual. Natural size. From the Inferior Oolite (Pea-grit) near Cheltenham . 193 



Fig. 4 a. The same. A portion of the interior fibre of the same specimen, enlarged seventy- 

 two timeSj showing relatively large axial three- and fouj'-rayed spicides, and 

 minute sinuous spicules bordering the fibre. The spicular structure is only 

 partially preserved. Drawn under the camera lucida from a transparent section. 



Fig. 5. Diaplectia helvelloides, Lamx. sp. Natui'al size. Showing the outer surface of 



the cup and the vertical disposition of the fibres 193 



Fig. 6. Elasmostoma scitulum, Hinde. Natural size. Showing the under or outer surface 



of a fan-shaped specimen. From the Upper Chalk at Bromley, Kent . . . 195 



Fig. 6 a. The same. The upper portion of another specimen from the same locality, 

 showing the upper or inner surface. Natural size. 



Fig. 6 6. The same. A portion of the surface of 6 a, enlarged eight times, showing the 

 raised margins of the circular apertures and the irregular perforations of the 

 interspaces between them. 



Figs. 6 c, d. The same. Two fragments of the interior fibres, enlarged seventy-two times, 

 showing large axial three- and four-rayed spicules, surrounded by smaller filiform 

 sinuous spicules. Drawn from transparent microscopic sections. 



Fig. 7. Elasmostoma crassum, Hinde. A portion of a specimen imbedded in chalk, 

 showing the upper or inner surface. Natural size. From the Upper Chalk at 

 Bromley, Kent 196 



Fig. 8. liaphidonema pustulatmn, Hinde. Natural size. A convolute specimen, showing 

 the oscular apertures on the under or outer surface of the wall. From the 

 Lower Green Sand at Farringdon, Berkshire 198 



Fig. 8 a. The same. A small cup-shaped specimen, showing the oscular apertures on the 

 inner surface of the wall. Natural size. 



Fig. 9. Trachysinia solitaria, Hinde. Natural size. From the Middle Jura : Couche h. 



Polypiers at Ilanville, near Caen 189 



Fig. 10. Trachysinia minor, Hinde. Natural size. From the Middle Jura at Ranville, 



near Caen 190 



