CHONDROCRANIUM OF EUMECES 205 
direct connection with the first branchial in one embryonic stage 
of Lacerta vivipara. This observation by Cords would seem to 
be conclusive, but the study of early stages of Eumeces leads me 
to question the character of the reported connection. Here also, 
in stages 1 and 2, the element in question is in contact with the 
first branchial at one point, and the two procartilage rudiments 
are hard to distinguish from one another. A careful study shows 
that this contact is a lateral one, and that the ends of the two 
structures are free in these embryos, as in stage 5. The contact 
and seeming union are probably only secondary. It is significant, 
in this connection, that Cords reports the problematic cartilage 
as arising from the first branchial at a sharp angle (‘mit einer 
scharfen Knickung’), and adds: ‘“‘Medial von der Knickungsstelle 
findet sich aus dem Vorknorpelstrang hervorgehend ein haken- 
formiger kleiner Fortsatz.’”’ This description suggests strongly 
a condition like that observed in early stages of Eumeces. The 
position and course of this isolated fragment, alike in early and — 
late embryos, suggest strongly a relation to the second branchial 
arch and make the derivation from the first branchial decidedly 
difficult. In the adult (Cope, fig. 29) the positions have shifted 
considerably, but the embryonic conditions are clearly more 
pertinent. A further study of the early development of this 
cartilage, in connection with that of the gill clefts, will be needed 
for a final determination of its homologies, but, for the present, 
I hold, with Gaupp, that the derivation from the second bran- 
chial arch is the more probable. 
Karlier and later stages show no conspicuous modifications 
of the hyobranchial apparatus. The arches are relatively longer 
in later stages. In stage 6 there is a striking flattening of the 
distal limb of the hyoid arch, just beyond the point of bending; 
in stage 5 of Eumeces this flattening is merely suggested, but 
it is conspicuous in Gaupp’s figure of Lacerta (05 b). During 
the development there is also a progressive tendency toward the 
breaking up of an originally continuous anlage into separate 
cartilaginous elements. In stage 5 there is a definite threefold 
division of the cartilage where the hyoid and first branchial arches 
meet one another and the body of the hyoid. This is shown in 
