TLATE IX. 



Page 



Fig. 1. Dory derma Benetti, Hinde. Natural size of the body and upper portion of the 



stem of a medium-sized example. From the Upper Green Sand at Warminster, 



Wiltshire 49 



Fig. 1 a. Tlie same. Part of the transverse section of the body of another specimen from 



the same locality, showing the distribution of the longitudinal canals. Natural 



size. 

 Fig. 16. The same. Portion of the outer surface of a specimen, enlarged eight times, showing 



the spicules and the interspaces of the mesh. 

 Fig. 2. Pachypoterion robustum, Hinde. Two thirds the natural size. From the Upper 



Green Sand at Pewsey, Wiltshire 52 



Fig. 2 a. The same. Portion of a transverse section of the lower portion of the body of 



another specimen from Pewsey, showing in section the canals which run in a 



generally vertical direction to the upper surface of the cup, and the appearance 



presented by the radial canals which run in a slightly arched direction from the 



outer surface to the centre. Natural size. 

 Fig. 2 b. The same. Portion of the spicular mesh of the interior as seen in a polished 



transverse section. Enlarged sixteen times. 

 Fig. 2 c. The same. Portion of the spicular mesh of the stem of another specimen from 



Pewsey. Enlarged sixteen times. 

 Fig. 3. Pachypoterion compactum, Hinde. The cup and the upper portion of the stem of 



a specimen from Warminster. Natural size. From the collection of William 



Smith 52 



Fig. 3 a. The same. Portion of the outer surface of the same specimen, enlarged sixteen 



times^ showing traces of the spicules and the mesh interspaces. 



