1927 



SYSTEMATIC 



45 



Table X — Dactylioceratid^ (Generic Analysis) 



I. Costate 



Anguidactylites 



Koinodactylites 



Leptodactylites 



Nomodactylites 



Orthodactylites 

 I. Costate 



A. Ribs small 



Kryptodactylites 

 Vermidactylites 

 I. Costate 



B. Ribs arched over venter 

 Arcidactylites 

 Athlodactylites 

 Curvidactylites 

 Microdactylites 



II. Tuberculate 



A. Tubercles persistent, 



regular 

 Zugodactylites 

 II. Tuberculate 



B. Tubercles intermittent 

 Parvidactylites 

 Tenuidactylites 

 Xeinodactylites 



II. Tuberculate 



c. Tubercles feeble 

 Dactylioceras 

 Peridactylites 



A geological sequence of the Dactylioceratid genera follows. The 

 numbers given (under ' Date ') refer to the Harrington Beds, see 

 S. Buckman, 1922, jam cit., and T.A. v, pp. 75, 76. 



Table XI — Dactylioceratid^ (Geological Sequence) 



II. Tuberculate 



D. Tubercles feeble, 



venter subangulate 

 Toxodactylites 

 II. Tuberculate 



E. Ribs broken on venter 

 Mucrodactylites 



III. Fibulate ornament 



A. Post-costate 

 Peronoceras 



III. Fibulate ornament 



B. Pre-costate 

 Multicceloceras 

 Nodicoeloceras 

 Porpoceras 

 Spinicoeloceras 



IV. Cadicone 



Catacoeloceras 

 Crassicoeloceras 

 Lobodactylites 

 IV. Cadicone 



A. To serpenticone 

 Simplidactylites 

 V. Venter carinatiform 

 Collina 



Genus 

 Catacoeloceras 

 Mucrodactylites 

 Collina 



Zugodactylites 

 Peronoceras 



{Multicceloceras 

 ParvidactyUtes 

 Arcidactylites 

 Nomodactylites 

 Koinodactylites 

 Curvidactylites 

 r Lobodactylites 

 I Peridactylites 

 / Leptodactylites 

 \ Spinicoeloceras 

 /Simplidactylites 

 I iToxodactylites 



Date or Bed 

 variabilis {grandis) 

 Upper Lias [late ?] 

 Upper Lias [late ?] 

 hraunianum 

 Cement Shale 

 Barr. 26 

 [B. 26?] 



subcarinalum [B. 26 ?] 

 Alum Shale 



Age 

 Haugian 

 Hildoceratan 



B. 

 B. 

 B. 



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