206 EDWARD L. RICE 
histological differentiation of the cartilage and in slight external 
grooves (fig. 4), but the three cartilages are in very close contact, 
probably in actual continuity. Stages 4 and 6 are identical in 
this respect with stage 5, but in stage 3 the two arches are per- 
fectly confluent with each other at this point, although divided 
from the body of the hyoid; in stage 2 the confluence includes 
the latter cartilage also, and there is an uninterrupted anlage 
for the entire hyobranchial apparatus, aside, of course, from the 
isolated ‘epibranchial’ just discussed. In no observed stage is 
there any suggestion of segmentation at the connection of the 
second branchial arch with the hyoid body, such as that in 
EKmys (Fuchs, ’07b; Kunkel, ’12b), nor at the bend of the 
hyoid arch, as figured by Osawa (’98, reproduced by Gaupp, 
05 b) in Sphenodon. This progressive articulation of the hyoid 
and branchial anlagen has been noted by Gaupp (’05 b) in Lacerta 
and by Fuchs (’07 b) and Kunkel (’12 b) in Emys. 
Uy 
10. SUMMARY 
The chondrocranium of Eumeces agrees closely with that of 
Lacerta in the main outlines of structure and development; in 
the following summary statement special emphasis is laid upon 
points of distinction, some of which are rather conspicuous and 
not without significance. 
1. Basal plate interrupted by large fenestra basicranialis 
posterior. 
2. Conspicuous intercondyloid incisure, bounded laterally and 
ventrally by large crescentic condylar surface—a type leading 
equally well to sauropsidan monocondyly or mammalian 
dicondyly. 
3. Cartilage of dens epistrophei seemingly confluent with that 
of basal plate. 
4. Notochord mainly dorsal to basal plate, but slightly em- 
bedded in latter posteriorly, especially in earlier stages; anterior 
extremity in regressive development, in earlier stages reaching 
and penetrating cartilage of crista sellaris, in later stages termi- 
nating freely in fenestra basicranialis posterior. 
