PLATE XLI. 



Pecten {continued). 



Figs. 



1—8. P. (Neithea) sexcostatus, Woodw. 1—5, Form (3, Upper Chalk. 6—8, 

 Form a, Lower Chalk. (P. 214.) 



1. A. quadratus zone, East Harnham, Salisbury. Dr. Blackmore's Collection. 



a, right valre ; b, portion of the two middle main ribs and part between x 4. 



2. Same horizon, etc. a, right valve ; b, posterior view of the same. 



3. B. mucronata zone, Hartford Bridge, Norwich. Woodwardian Museum. 



a, right valve x 1| ; b, portion of the same near the ventral margin x 4 ; 

 c, portion dorsal to middle of valve x 4. 



4. B. mucronata zone, Norwich. Norwich Museum. Right valve x 2. 



5. A. quadratus zone, East Harnham. Dr. Blackmore's Collection. Right valve. 



Portion of the two middle main ribs and part between x 4. 

 6 — 8. Chalk Marl, Do\er. Woodwardian Museum. Right valves. 6 a, X 1^; 6 b, 



posterior view of the same X 2 ; 6 c, part between two main ribs x 4. 7 a, 

 x H ; 7 b, posterior view of the same X 1^ ; 7 c, part between two main ribs 

 X 4. So, x li ; 8 b, part between two main ribs x 4. 



9, 10. P. (Neithea) striato co status ? Goldf. Chalk, Trimingham. Museum of 

 Practical Geology (Coll. Mr. Clement Reid). (P. 217.) 



9 a, portion of right valve ; 9 b, part of the same x 6. 10 a, left valve x 2 ; 

 10 b, part of the same x 5. 



Gen us — Velopecten, Philippi. 



11. T. Studeri (Pict. and Roux). LTpper Greensand, Warminster. York 



Museum. (P. 218.) 



11 a, left valve ; 11 b, part of the same x 2 ; lie, right valve of the same specimen. 



