PLATE XVII. 



LEPTOT>ESMA, pp. (Page 121.) 

 Fia. 



3. Specimen defective, but showing portions of the wings. Saunton Point (in a pebble). Hamling 

 Collection. 



AVICULOPECTEN NExiLis, Sotcerby, sp. (Page 129.) 



2. Portion of the surface of a specimen, x 15. Laticosta Cave, Baggy. My Collection. 



3. Slab, with moulds of the opposite valves, apparently of a single shell, x 3. Laticosta Cave, 



Baggy. My Collection. 



PTEBINOPECTEN SCABKIBADIANS, n. sp. (Page 135.) 



4. Specimen of a right valve, showing ornament and anterior wing clearly, but defective below, x 3. 



"Wrafton Lane. My Collection. 



PEBNOPECTEN INSPEBATTTS, n. sp. (Page 143.) 



5. Specimen, showing the projecting wings, x f. Top Orchard. Barnslaple Athenaeum. 



i 

 PROTHYBIS, sp. (Page 144.) 



6. Left valve, showing the anterior notch (which is fractured) and the radiating and transverse 



markings, x -f. Sloly Quarry. My Collection. 



EENSSELLJEBIA ? FOBMOSA, n. sp. (Page 145.) 



7. Specimen, showing umbonal arrangements and texture, but so much distorted as to simulate 



Leptsena laticosta in shape, x f . 7 a. Portion of surface, X 40. Poleshill. Porter Collection. 



8. Large specimen, sho\ving the cast of the dental plates, &c., and the rounded shape of the ribs, 



x f . 8 a. Umbonal portion, x 3. Ashford Strand. My Collection. 



9. Portion of the surface of a fragmental specimen, x 40, showing the pores and the shape of the 



ribs. Ashford Strand. My Collection. 





 ATHYBIS ? sp. (Page 146.) 



10, 10 a. Dorsal and lateral views of a minute undetermined species, x 6. Pilton. Porter Collection. 



ATHYBIS (SEMINULA) OBLONGA, Soiuerly, sp. (Page 147.) 



11. Cast of the closed valves, showing the slight marginal fold and indications of the marks left by 



the vascular sinuses, x 2. 11 a. Portion of the mould of the same individual, showing its 

 smooth surface, x 3. Ashford Strand. My Collection. 



12. Cast of the dorsal valve of rather doubtful specimen, which has a stronger and wider fold than 



usual, x f . 12 a, umbonal part, x 3. Barnstaple. Woodwardian Museum. 



ATHYBIS (CLEIOTHYBIS) EOYSSII, Leveille, sp. (Page 148.) 



13. Specimen figured by Davidson as Terelratula eJongata, Schlotheim (?), but exactly corresponding 



with casts of this species, x f. Braunton. Museum of Practical Geology. 



14. Cast of the ventral valve of a rather doubtful specimen, x 2. Roborough. Porter Collection. 



15. Mould of the ventral valve of a small specimen, showing the surface and the beginnings of the 



crura, X 2. 15 a, Umbonal part, x 5. Pilton. Porter Collection. 



