Zoology. : 943 
om that fact Gegenbaur reached the general conclusion 
that the ribs of all vertebrates are nothing else than the modifi- 
ations of the lower arches, the hemapophyses; or, reversed, 
the hemapophyses are ribs, 
ere are no lumbar vertebrae in Sphenodon, all the presacral 
ore have well-developed ribs, but the posterior ones are 
Uniting later with the vertebra. The two sacral vertebrae and 
œ anterior caudals show exactly the same condition; in the 
“ng animals the elements are free, but unite later with the 
the caudals we 
; 
Processes as those in Amia on which the ribs articulated. 
Jore the lower arches, which enclose the subcaudal blood- 
» are either formed by true ribs or by processes of the inter- 
Gege 3 nbaur was wrong in relation to the Stapedifera. Claus 
i that, but did not give any explanation of the con- 
Ashes 
pall tty to explain all the difficulties. 
S no doubt that the original condition is to be seen in 
ike Amia of the. Ganoids. | 
| Pi ur has shown that in many Teleostei the lower arches 
be med by the ribs, as in Amia, but by processes of the 
% 2° Which the ribs cah be articulated, This condition 
“i, in the given figures, 
Ten Same must have taken place in the higher Verte- 
. othe ribs were pushed out of place and dislocated, 
th “a Batrachia and Amniota.—In Archegosaurus the — 
ante, a 8ion are not connected with the well-devel- 
ra, but with diapophyses of the neural arches. In _ 
Sion € articular surface for the rib is continued | 
euy 
