superficial ophthalmic VII 



endolymphatic canal 



nner ear 



posterior cerebral vein foramen 



lateral rostral cartilage 



upper tooth plates 



clospei 



semicircular canals 



premaxillary labial cartilage 

 occipitospinal nerve foramina 



posterior cerebral vein foramen 

 maxillary lobial cartilage 



Figure 5-19. Cranium an6 lower jaw of Hydrohgus. A, dorsal view; B, ventral view; C, anterior 

 view; D, medial view of right half. 



medial rostral 

 sphenethmoid commissu 



efferent pseudobranchiol ortei 



superficial ophthalmic V| 



sphenethmoid commissure dorsum sellae ^ ^^j^ capsule 

 ethmoid chamber 



prootic incisu 



rostral cartilage 

 hypophyseal fenestra 



supraorbital cartilage 



hyomandibulor branch VII 

 dorsum sellae palatine branch V I 



superficial ophthalmic VII 

 pituitary vein foramen 

 dorsum sellae 



notochord 



orbitonasal foramen, V 

 medial rostra 

 lateral rostral cartilage 



Meckel's cartilage | otic process of quadrate cartilage 



orbital process 



Figure 5-20. Stages in the development of fhe head skeleton of Ca//orhynchus. A and B, lateral 

 and dorsal views of cranium and jaws of a 60-mm embryo; C, laterol view of head skeleton of 85-mm 

 embryo. (After Schainsland, 1903) 



124 • THE HEAD SKELETON OF FISHES 



