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Ormoceras

Classification

    Phylum:  
Mollusca
    Class:  
Cephalopoda
    Subclass:  
Actinoceratoidea
    Order:  
Actinocerida
    Family:  
Ormoceratidae
    Formal Genus Name and Reference:  
Ormoceras STOKES, 1840
    Type Species:  
O. bayfieldi, SD BASSLER, 1915


Images

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Fig. 150,1a. O. allumettense (BILLINGS), M.Ord., Can. (Que.); ventral view of weathered conch showing siphuncle, X0.7 (71). -- Fig. 150,1b. O. billingsi (FLOWER), M.Ord., Can.(Newf.); dorsoventral sec., X0.7 (l85). -- Fig. 150,1e,d. O. holmi TROEDSSON, M.Ord., Sweden; 1e, dorsoventral sec., X0.7; 1d, detail of septal neck (se, septum; sh, connecting ring; fu, septal neck; ch, camera; si, central canal; ea, radial canals), X2.7 (194)


Synonyms

Ormoceratites, Hormoceras, Sactoceras, Aluveroceras, Adamsoceras


Geographic Distribution

cosmop.


Age Range

    Beginning Stage in Treatise Usage:  
M.Ord.
    Beginning International Stage:  
Dapingian
    Fraction Up In Beginning Stage:  
0
    Beginning Date:  
471.26
    Ending Stage in Treatise Usage:  
Dev., ?L.Carb.
    Ending International Stage:  
Serpukhovian
    Fraction Up In Ending Stage:  
100
    Ending Date:  
323.4


Description

Medium-sized, straight shells, more or less circular in cross section, Siphuncle generally subcentral, segments almost globular, septal necks short, actinoceroid, with short brims, endosiphuncular canal system moderately complex to simple, radial canals few, Cameral deposits common




References



Museum or Author Information