68 



MORPHOLOGICAL TYPES 



On the floor of the brain-case are the basioccipital, pre- 

 vomer, and parasphenoid ; in front is the mesethmoid. The 

 roof is formed by the paired nasals, frontals, parietals, and the 

 supraoccipital. The foramen magnum, through which the 

 spinal cord enters the skull, is bounded below by the basi- 

 occipital, above by the supraoccipital, and on each side by the 

 paired exoccipitals. 



The auditory capsules are well ossified, and each contains 

 five bones. The lower part of each capsule is made of a prootic 



me. 



i 

 l 



Is hm. 



f. P^-mp. i sp. 



< l. sy. 



Fig. 35. — Gadus : view of a portion of the skull from the left side, after 

 removal of the lachrymal and suborbital bones, in order to show 

 the palato-pterygo-quadrate arch. {For lettering see p- 70.) 



in front and an opisthotic behind. Above these are the 

 sphenotic, pterotic, and epiotic bones. 



The sides of the brain-case are very incomplete. Anteriorly, 

 there are the paired prefrontals, between the frontal and the 

 parasphenoid on each side. Farther back the paired latero- 

 sphenoids are situated beneath the edge of the frontal and in 

 front of the prootic on each side. A large window is left open 

 in the side of the brain-case, through which many nerves and 

 blood-vessels pass from the skull to the space in which the eye 

 is lodged, called the orbit. Quite at the side there is a string 



