100 GENESIS OF THE ARIETIDiE. 



Neumayr ' includes what we consider the young of the radical species of 

 Agassiceras in his genus Cyrubites, and states that he has not found them in 

 the basin of the Northeastern Alps. Geyer, in his " Cephalopoden Hierlatz- 

 Schichten bei Hallstadt," figures and describes under the name of Cymbites a 

 characteristic young form of Agas. Icevigaium. Hauer's drawings of Amm. abnormis, 

 in his " Unsymmetrische Ammoniten der Hierlatz-Schichten," illustrate typical 

 shells belonging to the compressed variety of the same species, one of them 

 exhibiting the peculiar aperture, and another the gibbous young in the interior. 

 The radical species of the series, therefore, appeared in the Northeastern Alps 

 not earlier than the Upper Bucklandi beds, as in other faunas more or less 

 remote from the Cote d'Or. 



In the next subseries we find that Agas. Scipionianus and Scijrionis are char- 

 acteristic fossils of the Lower Bucklandi bed in the Cote d'Or and Rhone basins, 

 but in South Germany and England they appeared later, together with Agas. sala- 

 ries in the Upper Bucklandi bed, and in North Germany on the same horizon. So 

 far as known, no species of this subseries has been found in the Northeastern Alps. 



This series, therefore, has the aspect of having first appeared and met w r ith 

 a favorable home in the Cote d'Or or the basin of the Rhone, where its imme- 

 diate radicals are found. 



ASTEROCERAS. 



The asteroceran series is represented in the Northeastern Alps, though appar- 

 ently not by many forms. Hauer figures an Ast. obtusion, var. stellare, and we 

 have seen several specimens from this region, but the fauna evidently was not a 

 rich one as compared with those to the westward. According to Suess and 

 Mojsisovics, this species does not occur earlier than the Obtusus bed 2 in the strata 

 of the Osterhornes mountains, the Adnether-Schichten in which it appears being 

 placed by them above the Tuberculatus bed. According to our classification, 

 however, this curiously mixed fauna may have begun to receive migrants from 

 the west during the time of the lower bucklandian horizon. 3 



The first recorded appearance of Ast. obtusum occurred in the Upper Buck- 

 landi bed of South Germany, and in the similar formation of Luxemburg. 



M. Collenot, in his table of the forms in the Cote d'Or, quotes only the usual 

 three names, Amm. obtusus, stellaris, and Brooki. Boucault's collection in the 

 Museum of Comparative Zoology shows, however, that probably all the princi- 

 pal forms were present in the basin of the Cote d'Or, and the type of Ast. Col- 

 lenoti was certainly found there. Dumortier shows in his work, that this species 

 was also present in the Rhone basin, but the series of forms in the genus was 

 not otherwise so complete as in the Cote d'Or. The finest series exists in the 

 collection at the Museum of Stuttgardt. This does not have Collenoti, though it 



1 Ueber unvermit. auftret. Cephalopodentypen, pp. 63-65. 2 Op. cit., p. 198. 



3 The form cited by Wiihner, Ariet. stellceformis, an ally of Ast. obtusum, var. quadragonatum, is cited as 

 having been found in the Megasoma or upper part of the Angulatus beds in the Kamraerkahr Alps. This 

 is a doubtful matter, since only one specimen exists, and we have therefore allowed the text to stand 

 as written (Wiihner, Mojsis. et Neum., Beitr., VI., pi. xxvi., 1888). See also description of this variety, 

 Chapter V. 



