PLATE VI. 



Page 



Fig. 1. Jereica cylindrica, Hinde. A median vertical section showing the shallow cup and 

 sections of the canals. Natural size. Probably from the Upper Green Sand of 

 Wiltshire 43 



Fig. 1 a. The same. Spicules of the interior skeleton. Enlarged sixty-four times. Drawn 

 from a transparent microscopic section of the same specimen. 



Fig. 2. Stachyspongia spica, Roemer, sp. The upper portion of a specimen from the Grey 



Chalk, near Dover. Natural size 45 



Fig. 2 a. The same. Transverse section of another specimen from the same locality, showing 

 the central cloacal tube and sections of the horizontal canals. Natural size. 



Fig. 3. Scytalia fastigiata, Lee, sp. Natural size. From the Upper Chalk at Flam- 

 borough, Yorkshire 44 



Fig. 4. Scytalia radiciformis, Phill. sp. Natural size. From the Upper Chalk at Flam- 

 borough 44 



Fig. 4 a. The same. Transverse section of another specimen from Flamborough, showing 

 the central cloacal tube and sections of the horizontal canals which open into it. 

 Natural size. 



Fig. 4 b. The same. Spicules of the interior skeletal fibres. Enlarged sixty-four times. 

 From the Upper Chalk at Ahlten, Hanover. 



