6 WILLIAM K. GREGORY 
the alisphenoid bones, arise as rods or tracts of cartilage lying 
outside of and below the Gasserian ganglia and separated by 
them from the true brain cavity (fig. 3). In the embryonic 
skull these cartilaginous alae temporalis (fig. 3) spring from either 
side of the basisphenoid, very much as do the basipterygoid 
processes in the lizard skull (fig. 4); they also hold similar topo- 
eraphic relations with the carotid arteries. For these and similar 
reasons Gaupp does not hesitate to homologize the alae tem- 
Plan. suprasept. Fen. prootica Taen. marg. Caps. audit. 
= VA 
ya) ( 
pay a SY 
ENS 
BRASS St 
anh 
Septum interorb. 
Fen. optica Fen. 
metoptica 
Fen. Hypoph. Proe. Chorda_ For, N. facial. 
basipteryg. dors. 
Fig. 4 Chondrocranium of Lacerta agilis. From Gaupp (Merkel u. Bonnet’s 
Anat. Hefte, Ixi, 1902, fig. 5, p. 171). : 
The basipterygoid process, springing from the basisphenoid, lies outside of the primordial brain case 
and below the Gasserian ganglion, like the ala temporalis of mammals. 
poralis of mammals with the basipterygoid processes of reptiles. 
These processes he supposes to have become turned upward, so 
that they embraced the Gasserian ganglia externally; by further 
upgrowth of the replacing bone they covered the temporal region 
of the skull. The conclusion is drawn that the mammalian 
alisphenoids are not represented as such in the reptilian skull, 
that the pair of bones in the Crocodilia usually called alisphenoids 
represent some other elements. Accepting these views, Dr. von 
Huene (’11) applies them in the field of paleontology: ‘Die 
. 
