16 WILLIAM K. GREGORY 
(fig. 14) with the basipterygoid processes of the basisphenoid. 
If, in the Cynodonts, the cartilage fundaments (alae temporalis) 
of the alisphenoids (epipterygoids) had fused below with the 
basipterygoid processes, then, like the basipterygoid processes of 
lizards and like the alae temporalis of mammals, they would 
have been below the trigeminal roots and external to the 
openings for the carotids. 
Fig. 14 Under surface of developing skull of Sphenodon punctatus. (Howes 
and Swinnerton, Trans. Zool. Soc. vol. 16, pl. iv, fig. 16. Lettering modified.) 
The cartilage fundament of the alisphenoid (A.s.) is continuous with the basipterygoid process, 
below the postero-external branch of the pterygoid. This fact is shown in several of the stages figured 
by Howes and Swinnerton as well as in two wax models in the American Museum of Natural History 
which were made by Dr. Dahlgren from serial sections of Sphenodon embryos. 
In brief it is not difficult to conceive that all the parallel rela- 
tions noted by Gaupp between the alae temporalis of mammals 
and the basipterygoid processes of lizards are due, first to the 
derivation of mammals from Cynodont-like reptiles retaining 
certain primitive characters in common with the lizards, and 
secondly to the fusion of the cartilage fundaments of the pterygo- 
quadrate bars to the basipterygoid processes of the basisphenoid. 
