NO. 2.] DESCRIPTION OF THE FOSSILS. 



89 



trically bipartite, and its larger inner portion is again bipartite. The narrow, 

 second lateral saddle is symmetrically bipartite, as well as the small, first 

 auxiliary saddle. 



The lobe line is slightly asymmetrical. 



Among the ammonites, which Newton described from Franz Josef 

 Land, Amm. {Macrocephalites) marocephalus Sohloth. (1. c. PI. XXXIX. 

 fig. 1) may first of all be identified with Cadoceras Nanseni. Newton calls 

 this specimen (the first ammonite known from Franz Josef Land) "The true 

 Ammonites macrocephalus'' . Newton says further in his description: "In 

 these specimens the ribs pass outward from the small umbilicus and after 

 bifurcating run over the back without any forward flexure". Newton's figures 

 contradict these words. In Newton's fig. 1 the ribs in the first half of the 

 last preserved whorl are distinctly curved, as in the figures of our Cadoceras 

 Nanseni. When the ribs in the second half of the last whorl of Newton's 

 fig. 1. appear to be straight and an-anged radially, this — as is clearly visible 

 in the above-mentioned figure — is due to the fact that the anterior half of 

 the whorl is not intact, but is obliquely compressed. I examined numerous 

 specimens of all sizes of the typical Maorocephalites macrocephalus 

 Schloth. sp. (principally from Franconia); and none of them agrees with 

 Newton's Am,m. macrocephalus. The umbilicus in Macrocephalites macro- 

 cephalus Schloth sp. is always narrower, the involution greater than in 

 Amm. maorocephalus Newton— Cadoceras Nanseni n. sp. Furthermore, the 

 ribs in Macrocephalites macrocephalus Schloth. sp. are always finer and 

 closer together in young forms, always with a forward flexure in the middle, 

 and externally always less distinctly inclined forward than in Amm. macro- 

 cephalus Newton — Cadoceras Nanseni. It never happens in Macrocephalites 

 macrocephalus Schloth. sp. that besides the bifurcate and trifurcate ribs, which 

 always fork after the type mentioned under Macrocephalites sp. (cf. p. 68), 

 such a number of single ribs are interpolated as in Amm. macrocephalus 

 Newton (in Newton's fig. 1, five single ribs in the first half of the last whorl). 

 Single ribs, extending down to the umbilicus, are of the rarest occurrence in 

 the true Maorocephalites macrocephalus Schloth. sp. I could only prove their 



existence in very few young specimens. Newton's reference to Stephanoceras 



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