PLATE LVII. 



OsTRE.v {roiituiued). 

 Fios. 

 1—1:3. 0. semiplana, Sow. Upper Chalk. (P. 379.) 



1 — 4 Zone oi Belemnitella inucronata, Norwich. Norwiih Musouni. In, 2a, 9a, 

 4n, right valves. 16, 26, 36, 46, left valves. 

 5. TJintacrinus band, Thanet Coast. Dr. Rowo's Colloetioii. a, lift valve : 



6, Interior of tlie same ; c, rii,'ht valve of the same specimen, 

 fi. Zime of Behmnifella mticroiiafa, Hartford Bridi,'e, Norwich. Dr. I\owe"s 



C'olleotion. a, right valve; 6, left valve. 

 7. Same zone, Norwich. Norwiih Museum, a. leit valve; 6, interior of the 

 same. 

 8, 9. Uintacriniis band, Thanet coast. Dr. Rowe's Collection. 8, 9rt, right 

 valves ; 96, left valve. 

 10 — 12. Zone oi Belemnitella mucroiiafa, Norwich. Sedgwick Museum, Cambridge. 

 10, 11a, 12, right valves ; 116, left valve ; 126, posterior view of 12(1. 

 13. Same zone and localitv. Norwich Museum, No. 2130. Right valve. 



