555 
speaks of it under a different name — the interhyale — it is un- 
doubtedly the same thing. It has the same relative position and plays 
the same role in our interpretations, namely, that by means of it, 
the early continuity of the hyoid arch was established. At this period 
the short hyoid cornu extends from the central plate in a dorso- 
lateral direction toward the angle of the mouth and the processus 
ventralis, or interhyale, is direeted ventromedially, and one need 
only imagine an elongation of one or both of these elements to bring 
about the primitive condition. BENDERS use of VERSLUYS’ term 
“interhyale” seems more appropriate than “processus ventralis”’; 
it not only includes the latter in definition (“a ventrally directed 
process of the extra-columella’’) but its adoption would also bring 

Fig. 6. Fig. 7. 
Figs. 6 and 7. Embryo the same as for fig. 5. Sections show the relation 
of the interhyale to the extra-columella. m.c. Mecker’s cartilage; int. interhyale. 
Other abbreviations the same as before. 
about less confusion in homologizing the parts of the Chelonian 
columella with those of other forms. 
In this stage there is still no difference in the rate of development 
of the columella proper and the extracolumella. 
With the definition of the skeletal parts a closer relation has been 
established between them and the neighboring blood vessels and 
nerves (Fig. 5). The N. facialis, after leaving the Ggl. acustico- 
faciale, passes in a latero-caudal direction around the ventral end of 
the ear capsule, where between the capsule and the V. capitis lateralis, 
it enlarges, forming the Ggl. faciale. The course of the two main 
branches from this ganglion is the same as described in an early stage 
of development, with the addition that the posterior branch in its 
