374 ROBERT J. TERRY 



There is nothing in the model of the cat embryo to indicate 

 the presence of post-chnoid processes, which are found in the 

 bony cranium and are therefore formed later. These processes 

 in connection with the processus inter clinoideae, Voit regards as 

 vestiges of the primitive cranial wall in this region. Inter chnoid 

 processes have often been observed in the adult cranium of man, 

 and Fischer has noted them in the chondrocranium of Macacus. 



Foramen hypophyseos. The foramen hypophyseos is converted 

 into a canal by the growth in thickness of the floor of the sella 

 turcica. In embryos of 17 mm. the stalk of Rathke's pouch is 

 still intact as it hes in the canal. In the floor of the sella turcica 

 of the stage modeled, the hypophyseal canal is present, but only 

 vestiges of the stalk are apparent in it. Aral ('07) has described 

 a bony walled canalis cranio-pharyngeus in the cat, containing 

 a vein and a hypophysis accessoria cranio-pharyngei ; also an 

 epithehal-Uned bhnd canal interpreted as a possible vestige of 

 the stalk of Rathke's pouch. Voit has criticised Aral's homology 

 of the cranio-pharnygeal canal and the hypophyseal foramen in 

 the rabbit, asserting that the former is a secondary development, 

 occurring in a position caudad of the location of the hypophyseal 

 foramen. This criticism is not pertinent in the cat; the foramen 

 and the canal have the same location. 



Ala temporalis. Wincza ('96) described the boundary line be- 

 tween the ahsphenoid and basisphenoid (properly Ungula) in 

 embryos of the cat. My observations are in accord with this 

 description; a zone of perichondral tissue standing between a 

 chondrified processus alaris of the basis cranii and a broad car- 

 tilaginous plate, ala temporaUs, in relation to the Gasserian gan- 

 glion. The complete independence of the alisphenoid in the cat 

 led Wincza to investigate its relation to the cranium in other 

 mammals with the following results : In the dog embryo, a sepa- 

 rating zone was found between the cartilaginous alisphenoid and 

 basisphenoid; in embryos of the polar bear complete separation 

 of the two parts, with a small wedge-shaped cartilage in the 

 cleft; in man, a joint between alisphenoid and basisphenoid, re- 

 calling the relation between the head of the femur and the ace- 

 tabulum; in hedgehog embryos a boundary between the basi- 



