108 BULLETIN OF THE ESSEX INSTITUTE. 



uma the antorbital process does not become fused with the 

 lamina cribrosa. 



The quadrate is now supplied with a pterygoid process 

 {pt) which runs forward from the ventral surface of the 

 ascending process in close proximity with the ventral mar- 

 gin of the trabecula. Towards its anterior end it curves 

 laterally and broadens out into an oval plate. Its anterior 

 end lies a short distance postero-laterally from the base of 

 the antorbital process. Otic and palato-basal processes 

 unite the quadrate with the otic capsule. The stapes has 

 expanded into a broad plate nearly filling the fenestra 

 ovalis. It is still connected with the quadrate by a strong 

 stapedial process {sp). 



Characteristics of the Urodele Chondrocranium. 



From the preceding descriptions of the chondrocrania 

 of various Urodeles, we may briefly enumerate the more 

 important characteristics of the cartilaginous skull as found 

 in this group. 



Two occipital processes, the early history and relation- 

 ships of which have been more fully treated by Ph. 

 Stohr ('79), arise independently at the sides of the noto- 

 chord in front of the first permanent vertebra. The sim- 

 ilarity between these processes and those of which the 

 vertebrae are formed clearly indicates the vertebral nature 

 and origin of the occipital arch. From the sides of the 

 notochord the occipital processes pass upward, fuse with the 

 walls of the otic capsules and bend over medially to form 

 the synotic tectum (Fig. 18, ocp). Two large jugular 

 foramina are enclosed between the bases of the occipital 

 processes and the posterior ends of the otic capsules. 

 Parachordals, varying in size and extent from the narrow 

 bands of Desmognathus (Fig. 14, p) to the complete 



