54 STABILITY OF THE GENERA. 



among themselves like those of the Ampliioscus and of Homo 

 sapiens, between which imaginary evolution has worked, 

 according to theory, in nearly the same period of time. 



But the material facts discovered by palaeontology and 



accessible to everyone, dispel all illusion. In effect, the 



Nautilides, notwithstanding the great number of their 



specific forms, which must exceed 300, depart so little from 



their initial type, throughout the geological ages, that the 



merest novice would not hesitate in any case to recognize 



their generic nature. The variations or differences among 



the species, oscillate without any tendency to continue in a 



single direction so as to found a new type. In the actual 



fauna, Nautilus does not show, between its forms and the 



primitive forms, any greater differences than those which all 



naturalists agree in considering as purely specific. Even the 



Triassic Nautilides show less affinity to existing species than 



do the primitive forms. The theoretical evolution of the 



cephalopods, like that of the Trilobites, appears to us to be 



imaginary, without any foundation in fact.* 



Dr. Paul Fischer, in a notice of ]>arrande's work, whilst 



acknowledging the strength of the facts and observations brought 



forward by that distinguished palaeontologist against the de- 



velopment theory, does not consider them conclusive: " The 



type Goniatiies. says M. Fischer, has always been considered by 



evolutionists as a natural transition he! ween the Nautilus with 



its very simple partitions and the foliaceous sutures of the 



Ammonite; an opinion which is strengthened by the appear- 



ance of (Joiiiatites chronologically intermediate between the 



other two. In order to show the extreme (lillereuce which 



exists lie- ween the Nautilus and the (ioiiiat ites. M . P>arrau<le 



has studied the characters of the initial shell in these two genera 



a study which has acquired great importance since the publi- 



cation of Mr. Alpheus Hyatt's Fossil Cephalopoda." 



Mi-. Hyatt has shown that the initial chamber of Nai<Hlux 

 Pompilius shows au elongated nearly linear cicat rice, enclosed 

 by MII elliptical surface slightly depressed. He supposes that 

 the ovis.Mck was attached to the elliptic surface, and that the 



Kt.u(lrs<}<'nrr:iles,'' 224-280, 1ST?. 



