Die Ontogenese eines niedern Säugergehirns. 263 
Aus solchen Ueberlegungen entsprang bei mir der Entschluss, die 
Ontogenese des Igelgehirns zu verfolgen, da von allen für diesen 
Zweck erhältlichen Säugern Erinaceus unbedingt theoretisch und 
praktisch die günstigsten Aussichten darbietet. 
Die niedrige Stellung des Igels ist von vielen Forschern betont 
worden. So sagt HUXLEY !): 
„It is a fact, curiously in accordance with what might be expected 
on evolutionary principles, that while the existing members of the 
Prototheria and the Metatheria are all extremely modified, there are 
certain forms of living Eutheria which depart but little from the 
general type. For example, if Gymnura possessed a diffuse placentation, 
it would be an excellent representative of an undifferentiated Eutherian. 
Many years ago, in my lectures at the Royal College of Surgeons, 
I particularly insisted on the central position of the Insectivora among 
the higher Mammalia; and further study of this order and of the 
Rodentia has only strengthened my conviction, that any one who is 
acquainted with the range of variation of structure in these groups 
possesses the key to every peculiarity which is met with in the 
Primates, the Carnivora, and the Ungulata. Given the common 
plan of the Insectivora and of the Rodentia, and granting that the 
modifications of the structure of the limbs, of the brain, and of the 
alimentary and reproductive viscera which occur among them may 
exist and accumulate elsewhere, and the derivation of all the Eutheria 
from animals which, except for their simpler placentation, would be 
Insectivores, is a simple deduction from the law of evolution. There 
is no known Monotreme which is not vastly more different from the 
Prototherian type, and no Marsupial which has not far more widely 
departed from the Metatherian type, than Gymnura, or indeed, 
Erinaceus, have from the Eutherian type.“ 
Ausserdem ist Erinaceus eine durch hohes geologisches Alter 
gekennzeichnete Säugethiergattung. So sagt LECHE ?): ,,Sie“ [die 
Familie der Erinaceidae| ‚gehört zu den am frühesten auftretenden 
placentalen Säugethierfamilien, denn schon in den Phosphoriten des 
Quercy begegnet uns nicht nur Necrogymnurus, sondern auch ein 
wirklicher Erinaceus, welcher somit zu den ältesten der heute lebenden 
Säugethiergattungen gehört.“ 
Die im Allgemeinen niedrige und primitive Organisation des Igels 
und sein Fortleben in ziemlich unverändertem Zustande durch lange 
Ae. p. 657. 
2) LEcHE, 1896, p. 139. 
