PRIMORDIAL CRANIUM OF THE CAT 361 



rietal if not actual basal relationship and significance of the 

 commissure. The evidence of the parietal nature of the supra- 

 facial conmiissure may be considered at once, since upon its 

 interpretation depends to a large extent the question of the 

 cochlear relations to the basal plate. 



The relations of the suprafacial commissure in cat appear to 

 differ somewhat from those described in other mammals. In 

 Talpa, according to Fischer ('01), the roof of the facial canal is 

 made by a thin lamella of cartilage stretching from the pars 

 canalium semicircularium to the highest elevation of the coch- 

 lear capsule. Fischer regards the walls of the facial canal as 

 made entirely by the ear capsule, and contrasts this condition 

 with the formation of the canal in Lacerta, in which, as Gaupp 

 ('00) has found, the foramen for the seventh cerebral nerve lies 

 in the boundary zone between the basal plate and ear capsule. 

 Noordenbos ('05) named the roof of the facial canal the tectum 

 nervi fascialis, and found it connected with the medial wall of 

 the anterior ampullary swelling of the pars canalicularis. Voit 

 ('09) found, in the rabbit, that the suprafacial commissure 

 stretched from the anterior end of the pars posterior of the otic 

 capsule, beneath the prominentia utriculo-ampullaris posterior 

 and right above the superior acustic foramen, to the roof of 

 the anterior part of the pars cochlearis. In comparing the 

 facial foramen in rabbit and lizard, Voit evidently agrees with 

 Gaupp that, in mammals, the walls of the foramen are in part 

 contributed to by the cochlear capsule. In the dog, the supra- 

 facial commissure bridges over the facial foramen, from the 

 borders of the pars utriculo-canahcularis and the pars sacculo- 

 cochlearis, according to Olmstead ('11). De Burlet ('14) de- 

 scribed the commissura praefacialis of Balaenoptera rostrata 

 as a cartilaginous bridge between the pars cochlearis and pars 

 canalicularis. In De Burlet's plates VI and VII, however, 

 there is shown what appears to be a connection between the 

 praefacial commissure and lamina parietalis. The relations of 

 the lateral end of the suprafacial conmiissure in the cat differ 

 from those in the mammals mentioned, with the exception pos- 

 sibly of Balaenoptera. Connection between the conmiissure 



JOURNAL OF MORPHOLOGY, VOL. 29, NO. 2 



