AT 
much simplified. The antagonism between head and 
trunk, the invasion of the trunk-myotomes into the occipital 
region, the “stetiges Vorrücken of the former (FüRBRINGER, 
1897, p. 440), the struggle between the neural crest of fhe head 
and that of the trunk, the hand to hand contest between the 
dorsal and ventral roots of the two enemy regions, all painted 
to us by FRORIEP (1901, p. 372) as the “heiszen Kampf 
der Theile’, fade away like a fata morgana: peace and 
rest appear to reign in the occipital region. 
Hypoglossus of Amniotes. — The question has been partly 
answered already as to whether in the case of the hypoglos- 
sus in Amniotes, the “occipito-spinal” nerves of FüRBRINGER, 
there is more reason to assume all these complicated displace- 
ments than in that of the occipital roots in Elasmobranchs, to 
which the hypoglossus shows such an undeniable resem- 
blance. Is the distinction between a protometameric and 
an auximetameric neocranium a firmly founded one? These 
terms, introduced by FüRBRINGER, are found in every 
text-book, every student knows them (and if he does not, 
he will have a bad chance in his examination) and their 
general acceptance seems to allow hardly any doubt as 
to the correctness of this distinction. According to it, three 
of the anterior spinal nerves of Elasmobranchs and Amphi- 
bians, 1, 2, and 3 — at least their ventral roots, the dorsal 
ones having again atrophied — have been incorporated in 
Amniotes as a, b and c (occipito-spinal nerves) into the 
cranium to which accordingly once more a corresponding 
number of vertebrae has been assimilated. These three 
ventral roots form the hypoglossus which, together with 
the anterior spinal nerves, innervates the tongue-musculaturc 
which is to be derived from the hypobranchial muscles of 
Elasmobranchs. At exactly the same place where in the 
latter the “ventral vagus roots” are found, that is right 
under the vagus and its derivative the accessorius, which, 
as shown e. g. by VAN BEMMELEN (1889), arises in close 
connection to the rudimentary dorsal ganglia behind the 
vagus, we find in Amniotes the hypoglossus-roots. Once 
more, according to FüRBRINGER, we must assume such an 
tmprobable moving of ventral roots (and corresponding 
myotomes) in forward direction over a distance of several 
segments till they have arrived right under the dorsal 
roots of segments far in front of them, a displacement for 
Which not a single reason can be given. On the contrary, 
