FAUNA OP mi". PROVINCE OF CENTRAL EUROPE 107 



if the Planorbis sone; they were immediately succeeded in the Angulatua 

 Eone liv a full presentation <>t' achlotheimian, caloceran, and vermiceran bj 

 that is, ol the entire Plicatua Stork. This stock then entered upon ;i period of 

 lence, slight in the Lower Bucklandi, but more marked in the Upper Buck- 

 landi bed. Arnioceras attained its greatest development in the Upper Bucklandi 

 ■one and was more persistent in the higher beda than Coroniceras, Thi> last 

 attained its fullest expansion earlier in the Lower Bucklandi beds, and declined 

 rapidly in tin- Upper Bucklandi, and disappeared altogether in the Obtusua bed 

 . shown by tin' ius characteristica of the Bpeciea in the 



Bucklandi beds, rather than by a le-s number of forms. Thus Cor. orbicu- 

 . i, . and the multicostatw variety of bi ire all 



im pared with the forms of the Lower Bucklandi bed. 

 They have mon nt-sided whorls, and these are usually developed at an 



earlier 



reached its acme in the Lower Bucklandi bed, but is more 



•ue tonus in the higher formations Asti roceraa is the only 



which attained its acme in the Obtusua /one. and then declined in the 



The oxynoticeran series reached its maximum in the Oxynotua 



Bone, ami. though Burviving the changea which attended migration into middle 



me- extinct in that formation. 



The Bchlotheimian Beriea i- a highly i lified Beries, composed of involute 



. and ceased t<> exist in the < Hit nsu- bed, bul there are a few 



dwarfed forma in the Oxynotua lied. Caloceraa persisted in the highest beds, 



when bly modified derivative Beries, Vermiceras, is shorter lived, and 



I in the highest beds. Arnioceraa ia parallel with Calo- 



and is the radical Beriea from which the more highly modified and 



shorter lived Coron tinted. Agassiceras, the radical of the remaining 



from the Angulatus to the Oxynotua bed, whereas the deriva- 



1 were both Bhorter lived. Thi even 



when tlius minutely followed out, accord with the law of persistence in radical 



I'- loci i is itself i- not persistent, and 



i- an apparent It is the last of a long line of paleozoic secondary 



lis which Burvived in the Lower Lias. It can be compared with the 



upper part oi' .1 stem which ha- reached the point <>i growth at which it splits 



man) branches. Psiloceraa waa in like mannei into derivative 



• ian radicals ( 'dor. ' \ 



We have aln ted and discussed the rise ami proj 



id. the acme : third, the final decline, 01 



i by the prevalence of geratologous forms. The result of such a 



iry, when the -■ onsidercd together a- one family found within 



■ died beds, i- shown in thi- table. I parnllelism 



n the hi.Htorv of the whole and of any 01 I norbis and 



1 if 



tionkl t ' 



