1S93.] MR. ir, r. woodw^vrd on mammalian dentition. 471 



viz. m. 1. One of the most important factors in the modifica- 

 tions which we meet with in the Mammalian dentition is the 

 shortening of the jaws, often accompanied by an enlargement of 

 some of the teeth, thus causing a reduction and finally a suppres- 

 sion of some of the series. These missing teeth can be sometimes 

 discovered through the study of Pateontology, sometimes through 

 the study of Abnormalities, but the surest method when possible 

 is by the study of their development. 



The great variability of the anterior premolar of the living 

 Placentalia and the insignificance of our knowledge concerning it, 

 as to which dentition it is to be referred, alone show how futile 

 are our attempts to homologize the dentition's of the leading 

 orders of living Mammalia. And, reflecting upon the facts which 

 I have herein recorded, I believe that our greatest desideratum at 

 present is the further study of the development of the teeth of 

 these animals, especially in its bearing upon the probable discovery 

 and determination of vestigial teeth. 



My thanks are due to Prof. Howes for much valuable advice, 

 and to Mr. Fletcher of Sydney, Dr. Symington, and Mr. Oldfield 

 Thomas for gifts of much valuable material. 



IV. — List of Eefeeences. 



1. Batjme. — Versuch einer Entwicklungsg. d. Gebisses. Leipzig, 



1882. 



2. Cope. — "The Mechanical Cause of the Development of the 



hard parts of the Mammalia." Jour. Morph. vol. iii. 1889. 



3. Floavee, Sir W. H. — " On the Development and Siicces-iion 



of the Teeth in the Marsupiaiia." Phil. Trans, vol. 157. 

 p. 631 (1867). 



4. KiJKENTHAL, W. — " Einigo Bermerkungen lib. d. Saugetier- 



Bezahuung." Anat. Auz. 1891, p. 364. 



5. KtTKENTHAL, W. — " Das Gebiss V. Dklelpliijs." Anat. Anz. 



1891, p. 658. 

 These two papers are iranslated in the Ann. Mag. Nat. Hist. 

 ser. 6, ix. pp. 279, 285 (1892). 



6. Leche. — " Studien iiber d. Entwick. d. Zahnsystems b. d. 



Saugethiereu." M. J. xix. 1893, p. 502. 



7. Owen.— Art. " Teeth " in Todd's Cyclop. 

 Oaven. — Mesozoic Mammals. Pal. Soc. 



8. Pouchet et Chabey. — " Cont. a I'Odontologie d. Mammif." 



J. Anat. et Physiol. 1884. 



9. EdsE "IJeber d. Zahnentwicklung d. Beuteltiere." Anat. 



Anz. 1892, p. 693. 



10. Thomas, O.— " On Dr. Kiikenthal's discoveries in Mammalian 



Dentition." Ann. Mag. JS'at. Hist. ser. 6, ix. p. 308 (1892). 



11. Thomas, O. — "On the Homologies and Succession of the 



Teeth in the Dasyuridce, with an attempt to trace the 

 history of tlie evolution of the Mammalian Teeth in 

 general." Phil Trans, vol. 178. pp. 443-462 (1887). 



12. Thomas, O.— Catalogue of Marsupials Brit. Mus. 1888. 



32* 



