CONTENTS 

 Part XXI 



Text : — 



Chronology 



Illustrations : — 



137. Am. victoris, Homoeomorph of 



(Tutchericeras perfoliatum) 



139. Am. biplex, Homoeomorph of 



(Dichotomoceras dichotomum) . 



148. Ammonites placenta 



(Longaeviceras placenta) 



149. Ammonites lamellosus 



(Phricodoceras lamellosum) 



150. A mammillate Sonninia 



(Papilliceras papillatum) 



151. Ammonites braikenridgii 



(Epalxites formosus) 



152. Ammonites braikenridgii 



(Masckeites densus) 



153. Stephanoceras zigzag 



(Procerites euryodos) 



154. Ammonites lamberti 



(Lamberticeras lamberti) 



155. Ammonites serratus 



(Prionoceras prionodes) 



Page 

 9 



Plate 

 CXXXVI1 b 



CXXXIX b, c 



CXLVIII 



CXLIX a, b, c 



CL a, B 

 CL1 

 CL1I 



CL11I 



CLIV 



CLV 



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