PLATE VIII. 



Page 

 Fig. 1. Dory derma dichotomum, Benett, sp. Natural size. From the Upper Green Sand 



at Warminster, Wiltshire 47 



Fi"-. 1 a. The same. Transverse section of a branch of another specimen from the same 



locality, showing sections of the longitudinal canals. Natural size. 

 Fig. 1 b. The same. Portion of the surface of 1 a, enlarged eight times, showing three of 



the canals and the disposition of the spicular mesh. 

 Fig. 2. Doryderma ramosum, IMantell, sp. Portion of a specimen from the I'pper Chalk 



at Oare, Wiltshire. Natural size 48 



Fig. 2 a. The same. Portion of the outer surface of the same specimen, enlarged sixteen 



times, showing the spicular structure and the interspaces of the mesh. 

 Fig. 3. Doryderma Rcemeri, Hinde. A fragmentary specimen inclosed in a flint from the 



Upper Chalk of Wiltshire ? Natural size 49 



Fig. 3 a. The same. Portion of the outer surface of the same specimen, showing the dispo- 

 sition of the spicules and the mesh-interspaces. Enlarged sixteen times. 

 Fig. 3 b. The same. Two of the minute trifid spicules with which the interspaces of the 



mesh at the surface are filled. Enlarged sixteen times. From the Upper Chalk 



at Ahlten, Hanover. 



