PLATE XVI. 



Fig. 

 1, Ptygmatis velox, Witchell. Oolite Marl, Longridge. My Collection. (Page 

 221.) 



2 a. Ptt/pnatis Stroudiensis^ Witchell. Oolite Marl, Longridge. 2 b. The same, 



Swift's Hill. My Collection. (Page 222.) 



3 <7, ^ b. Ptijgmatis Cotteswoldice, Lycett. Pea-grit, Longfords. 3 c. The same. 



Fragment showing natural section. Lincolnshire Limestone, Dene. 

 3 d. The same. Lincolnshire Limestone, Belmisthorpe. My Collection. 

 (Page 222.) 



4 a. Ftygmatis Cotteswoldia , Lycett, var. conica, Witchell ; type refigured. Oolite 



Marl, Swift's Hill. Witchell Collection. 4 b. The same, showing 

 section of interior. Oolite Marl, Longridge. 4 c and 4 d. Possibly 

 the same, with worn surface — a common form in the Oolite Marl, 

 Longridge. My Collection. (Page 223.) 



5. Specimen of Ptygmatis with the aperture and canal well preserved. Oolite 



Marl, Longridge. My Collection. N.B. — This probably represents 

 the true form of aperture in this group. 



6. Ptygmatis, species or variety. Oolite Marl, Swift's Hill. My Collection. 



(Page 224.) 



7. Ptygmatis ? -pisolitica, Witchell. Fragment from the Lincolnshire Limestone, 



Weldon. My Collection. (Page 215.) 

 8 a. Ptygmatis Santonis, sp. nov. Oolite Marl, Longridge. My Collection. 8 &, 



8 c. The same. Lincolnshire Limestone, Santon. Jermyn Street 



Museum. (Page 224.) 

 9a. Ptygmatis brevivoluta, sp. nov. 9^. The same; specimen cut longitudinally, 



X 2. Clypeus-grit, Barrington. My Collection. (Page 225.) 



10. Ptygmatis i' brevivoluta, y. 1^. Lincolnshire Limestone, Weldon. My Collection. 



11. Ptyymatis " sub-brevivoluta." Lincolnshire Limestone, Weldon. My Collection. 



(Page 226.) 



12. Ptygmatis ? bacillus, D'Orb. (rolled fragment). Lincolnshire Limestone, 



Weldon. My Collection. (Page 217.) 



