PLATE XXXIX. 
Prcten (continued). 
Fias. 
1—5._ P. (Neithea) atavus, Rom. Lower Greensand, Upware. 1,5, Mr. J. F. 
Walker’s Collection. 2, 3, 4, Woodwardian Museum. (P. 197.) 
1, right valve. 2, left valve. 3a, right valve; 3b, posterior view of both valves. 
4a, right valve; 4 6, portion between the two middle ribs of left valve x 3; 
4c, portion between the two middle ribs of right valve x 3. 5, portion 
between the two middle ribs of right valve x 4. 
6—10. P. (Neithea) cometa (d’Orb.). Upper Greensand, Warminster. (P. 200.) 
6. British Museum, No. 38267. Right valve. 
Woodwardian Museum. a, right valve ; 6, posterior view of the same ; c, anterior 
view of same. 
8. British Museum, No. 88871. Left valve. 
9. Museum of Practical Geology, No. 8278. Right valve. 
10. Same museum, No. 8445. Portion of right valve x 4. 
11—13. P. (Neithea) Morrisi (Pict. and Renev.). (P. 201.) 
11. Hythe Beds, Lympne. Museum of Practical Geology, No. 8364. a, right 
valve; b, posterior view of the same; c, portion between two main ribs x 3. 
12. Same locality, etc., No. 8446. a, left valve; 6, posterior view of the same. 
13. Perna-bed, Atherfield. Woodwardian Museum. Left valve—posterior margin 
restored. 
14—17.  P. (Neithea) quinquecostatus, Sow. (P. 202.) 
14. Upper Greensand, Ventnor. York Museum. a, right valve; b, anterior view 
of the same. 
15. Upper Greensand (zone of Pecten asper), Shaftesbury. Bristol Museum. 
a, right valve; b, left valve; c, anterior view. 
16. Same horizon, Warminster. Museum of Practica] Geology, No. 8419. a, right 
valve; b, anterior view of the same. 
7. Upper Chalk (? M. cor-anguinum zone), Gravesend. Museum of Practical 
Geolozy, No. 8362. a, right valve; 6, left valve; c, posterior view of the 
same specimen. 
—_ 
~ 
