Fig. 



:^6. ,, depressa, Sow. var. Farringdon. 



27. ,, nuciformis, Sow. ? Upper Green Sand, Isle of Wight. 



28. „ depressa, Sow., var. B. Chalk, with chloritic grains of Chardstock 

 28* c . ;; „ Enlarged. 



28". „ „ Young. 



29. ,, ,, var. ? Upper Green Sand, Shaftesbury. 



30. ,, ,, var. A. Chardstock. 

 30°'. ,, „ Enlarged. 



31. Argiope Megatrema, Soto., sp. Original figure, 'Trans. Geol. Soc.' 

 31". „ „ Enlarged. 



32. ,, ,, Upper Green Sand, Warminster. 



32. ,, ,, Enlarged. 



33. ,, Buchii, Be Hagenow? Lower Chalk, Kent. 

 33'' ,, ,, Enlarged. 



34. ,, Megatreraa=r(decemcostata, Reenter). Upper Green Sand, Cambridge. 

 34 a4 ,, „ Enlarged. 



35. ,, ., Rcemer's original figure. 

 35". „ „ Enlarged. 



36. ,, ,, A specimen of the same, from Essen. 

 30". ,, ,, Enlarged. 



37. ,, Bronni, Be Hagenow. His original figure. 



38. ,, Bucchi, „ Ibid. 



Nota. — Figs. 35 to 38, have been introduced to facilitate comparisons with our 

 British examples, upon which some uncertainty appeared to exist. 



39. Thecidiunl Wetherelli, Morris. Sponge Gravel, Farringdon ; interior of the 



ventral or dental valve. 



39". „ „ Enlarged. 



40 to 41. Crania cenomanensisj B'Orb. Farringdon. Fig: 40, lower valve; 41", en- 

 larged; 41, upper valve; 41", enlarged. 



