374 



large and approximated elliptical optic foramina ; a deep and narrow groove extends from the 

 optic fossa to the rhinencephalic compartment, where it divides to terminate at the orbito- 

 ethmoidal foramina. The foramen rotundum and foramen lacerum anterius combine to form 

 a large subquadrate vacuity. The cerebellar fossa on the upper part of the petrosal is very 

 deep. The meatus internus is extremely shallow, and almost immediately divides into the 

 cochlear and vestibular canals. 



2053. The left ramus of the lower jaw. 



2054. The atlas. 



The transverse process is perforated horizontally and vertically, and the neural arch is also 

 perforated on each side on both its anterior and posterior borders. 



2055. The axis. 2056. The middle cervical vertebra. 



2057. An anterior dorsal vertebra. 



2058. Four succeeding dorsal vertebrae. 



They show the progressive development of the metapophysis. 



2059. Four posterior dorsal vertebrae. 



They show the progressive development of the anapophysis. 







2060. A lumbar vertebra. 



It shows the distinctness of both these accessory processes from the zygapophyses and the 

 diapophyses. 



2061. The sacrum. 



It consists of four anchylosed vertebrae : the first is remarkable for the elevation of its 

 spine. 



2062. The caudal vertebrae. 



They are 1 1 in number. The neurapophyses are not united together in the seventh, but 

 terminate above in tuberosities which bound the sides of an open neural canal. The tail is 

 strongly bent upwards from this vertebra. Hypapophyses are developed beneath the fourth 

 caudal, and distinct haemapophyses are articulated to the interspaces of the succeeding ver- 

 tebrae as far as the penultimate one. 



