CLASSIFICATION, AND PHTLOGENY OP THE DINOENITHID^. 407 



9. l^'idth of cranium at preorbital jjrocesses : length of a straight line joining the 

 posterior borders of the lacrymals. 



10. Distance letween temporal ridges : length of the shortest straight line joining 

 the right and left temporal ridges. 



11. Height of cranium : length of a perpendicular from the highest part of the 



cranial roof to the basitemporal platform. 



12. Width of tympanic cavity: length of the longest horizontal straight line joining 

 the posterior temporal ridge and the edge of the paroccipital process. 



13. Width of temporal fossa : length of the longest horizontal straight line joining 

 the anterior and posterior limbs of the temporal ridge, above the junction with 

 the latter of the posterior temporal ridge. 



14. Width of orhit : length of the longest horizontal straight line joining the posterior 

 border of the lacrymal and the anterior border of the postorbital process. 



15. Distance bettueen optic foramina : length of a straight line joining the lower 

 borders of the foramina. 



16. Greatest length of premaxilla : from apex of body in a straight line to posterior 

 end of nasal process. 



17. Length of premaxilla to end of maxillary process: from apex of body in a straight 

 line. 



18. Length of body of premaxilla : length of a straight line between apex and 



posterior border of preuarial septum. 



19. Width of body of premaxilla : length of a straight line between the right and 

 left alveolar borders at the level of the posterior edge of the prenarial 

 septum. 



20. Length of maxillo-jugal arch : the greatest length in a straight line. 



21. Length of vomer: the greatest length in a straight line. 



22. Length of palatine : the greatest length in a straight line. 



23. Lmigth of pterygoid : the greatest length in a straight line. 



24. Length of quadrate : length of a straight line from the articular surface of the 

 head to the most prominent part of the internal condyle. 



25. Length of mandibular ramus : from middle of anterior border of symphysis to 



extremity of posterior angular process. 



26. Greatest height of mandible : length of a perpendicular from the coronoid process 

 to the ventral border. 



27. Least height of mandihle : a similar measurement of the anterior part of the 



ramus a short distance posterior to the symphysis. 



28. Length of mandibular symphysis : length of a straight line passing from the 



middle of the anterior to the middle of the posterior border of the symphysis. 



29. Width of mandibular symphysis : length of a straight line between the right and 

 left alveolar borders at the level of the posterior edge of the symphysis. 



3m2 



