406 



HARRIS HAWTHORNE WILDER ON 



and thus strengthening the impoi'tant articulation of the head with the vertebral column, 

 and (3 and 4 ) two ossifications of the otic capsule. These, of which the anterior is the 

 pro-otic, and the posterior the epi- and opisthotic combined, are in the form of hollow cups 

 which fit over the anterior and posterior ends of the otic capsule, looking, to borrow W. 

 K. Parker's vivid simile (in Proteus), "as if they were ready to dehisce transversely like 

 the pyxidium of the pimpernel (Anagallis) ." 



The Osseous Elements. 





aLa 



.. aLa 



fcss^ f»» owe-*'* 





The otic and occipital regions. — 1. pro-otic. This very irregular bone consists 

 essentially of a conical cap to which are added four projecting processes, one upon the 



inner and three upon 

 the outer aspect. The 

 inner process, the ala, is 

 flat and wing-like and is 

 applied along the outer 

 edge of the base of the 

 trabecula. Of the three 

 processes which project 

 from the external face 

 of the bone, tlie two an- 

 terior ones, dorsal and 

 ventral quadrate proc- 

 esses, possess concave 

 and rouiihened articular 

 surfaces to receive cor- 

 responding processes of 

 the quadrate cartilage. 

 The ventral process 

 may be considered an 

 extension of the ala, and it receives a rounded protuberance situated in the middle of the 

 posterior margin of the cartilaginous quadrate. The dorsal quadrate process forms the 

 external dorsal edge of the bone and displays a more elongated articular surface foi- the 

 reception of the otic process of the quadrate. The i-emaining external process has no 

 relation with otlier skeletal parts and its probable use is that of attachment for some 

 important muscle or hgament, as it is very constant in appearance and always well 



DoaSAL 



Fig. 8. Four views of tlie rifcht pro-otic. p. (j. (1., dorsal <iuatlrate proce.ss ; p. q. v., 

 ventral quadrate process ; f. sty. m., stylo-ma.stoid foramen. 



