NO. 2.] DESCRIPTION OF THE FOSSILS. 79 



Cadoceras Milaschevici Nik. (= compressum Nik.) 

 „ patruum Eichw. sp. 

 „ galdrinum d'Orb. sp.(?) 



From the two most important species I designate this group as that of 

 "Cadoceras sublceve Sow. sp. and Tchefkini d'Orb. sp". 



A series of other species is closely allied to Cadoceras modiolare d'Orb. 

 sp. being characterised in their earlier stages by thicker whorls with a wider 

 umbihcus, and generally coarser and less distinctly falciform ribs. At more 

 advanced stages of growth also, coarser ribs and a wider umbilicus remain 

 characteristic of these species: 

 Amm. sublcevis macrocephali Quenstedt (Cephalopoden p. 177, PI. 14, fig. 6.) 



„ „ Quenstedt (Amm. d. Schwab Jura PI. 79, figs. 2, 3, 4.) 



Amm. sublcevis Quenstedt (1. c. PI. 79, fig. 5) according to Nikitin an interme- 

 diate form between Cadoceras Frearsi d'Orb. sp. and Surense 

 Nik. 

 Amm. sublcevis Quenstedt (1. c. PI. 79, fig. 6.) = Cadoceras modiolare Nik. 

 this species is entirely different from Cad. modiolare d'Orb. 

 sp., as the ribs become very broad even at an early stage. 

 Amm. sublcevis Quenstedt. (1. c. PI. 79. fig. 7.) = Cadoceras cf . modiolare Nik. 

 Furthermore they are joined by the kindred species of Cadoceras Elatmae 

 Nik. from the Russian Jura: 

 Cadoceras Elatmae Nik. 



„ Frearsi (d'Orb.) Nik. 



„ modiolare Nik. non d'Orb. sp. 



„ Surense Nik. 



To these belongs perhaps also Cadoceras sublceve E. Desl.^ non Sow. sp. 

 from the Lamberti strata of Villers-sur-mer, with a rather narrow umbilicus. 

 From the most important species, this group may be designated as the Cado- 

 ceras modiolare d'Orb. sp. and Elatmm Nik."^ Group. Both these briefly 

 sketched groups are also represented in the collection of Cadocerates from 

 Gape Flora, now before me. 



* E. E. Deslongchamps, 'Rapport sur les Fossiles oxfordiens de la collection farry' Bull 

 d. 1. Soc. Linn^enne de Normandie, 1889, (Extr.) p. 26, pi. I. figs. 1—4. 



'' Owing to the scarcity of material, I was not able to determine to which group Cad. 

 subpatruum Nik. Schiimarowi Nik. ought to be referred. 



