^55 



inferior pre-molar is much larger (Plate XXIX., C. 2), and is frequently 

 cast before tlie first, but, as a rule, they are generally shed together 

 at ages varying from one year and nine months to two years and three 

 months. The second upper temporary pre-molar (6) is usually replaced 

 by a permanent one, between tivo years and three months, and tivo 

 years and nine months. The third inferior temporary pre-molar is 

 remarkable in having three distinct sections, or columns (Plate XXIX., 

 C. 3), and resembles the sixth permanent ; it is very much larger 

 and longer than the second, and is cast (7) between two years and 

 three months and two years and nine months. Shortly after this (8) the 

 third superior pre-molar is shed. I have seen the third superior pre- 

 molar come off before the second, and have also removed them both 

 together (Plate XXIX, B. 2 and 3 J. 



361. The following plate, representative of one side of the under 

 jaw, shows the age when the permanent molar teeth are cut, and 

 when the three first temporary pre-molars are cast and replaced 

 by permanents : — 



Permanent Pre-molars and Molars of the Cow. 

 P.M., 2 years 3 months to 2 years 9 months. 



P.M., from I year and g months 

 to 2 years and 

 3 months. 



6.P.M 



T.M 



T.M. at Birth. 



P.M. at 6 months. 



P.M. at 15 months. 



T.M.— Temporary Pre-molars. 

 P.M. — Permanent Molars. 



P.M. at 2 years. 



