444 PROCEEDINGS OF THE ACADEMY OF [1892. 



in the artiodactyls the order is proto-, trito-, tetarto- and deutero- 

 eones. D* in the same group has a cusp internal to the paracone, 

 which seldom appears in other types. 



7. So far as the homologies of the cusps in the premolars and 

 milk molars are concerned, the results of paleontology agree exactly 

 with those of embryology. 



List of Papers Quoted. 



1. Cope, E. D. The Origin of the Fittest. New York, 1887. 



2. Cope, E. D. Tertiary Vertebrata. Washington, 1884. 



3. Dybowski, B. Studien viber die Siiugethierzahne. Verb. d. k. 



k. Zool.-botanisch. Ges. Wien, 1889, p. .3. 



4. Fleischmann, a. Die Grundform der Backziihne bei Sauge- 



thieren. Sitzungsberichte d. kon. preuss. Akad. d. Wis- 

 senschaften zu Berlin, 1891, p. 891. 



5. Mahn, R. Bau und Entwicklung d. Molaren bei Mus und 



Arvicola. Morphologisches Jahrbuch, Bd. XVI, p. 652. 



6. Marsh, O. C. A New Order of Extinct Eocene Mammalia. 



Amer. Journ. of Sci. and Arts, 3rd Ser., Vol. XLIII, 

 p. 445. 



7. OsBORN, H. F. The Evolution of the Mammalian Molar to 



and ffom the Tritubercular Tyj)e. Amer. Naturalist, 

 1888, p. 1067. 



8. Rose, G. Ueb. d. Entstehung und Formabanderung d. mensch- 



lichen Molaren. Anatom. Anzeiger, 1892, Nr. 13 and 14. 



9. RiJTiMEYER, L. Beitr. zu einer natiirl. Gesch. d. Hirsche. 



Abb. d. schweiz. pal. Gesellschaft, Bd. X. 



10. ScHLOSSER, M. Die Affen, Lemuren, etc., d. Europ. Tertiiirs. 



11. Scott, W. B. The Osteology of Poebrotherium. Journ. of 



Morphology, Vol. V, p. 1. 



12. Taeker, J. Zur Kenntniss d. Odontogenese bei Ungulaten. 



Dorpat, 1892. 



13. Thomas, O. On the Species of Hyracoidea. Proc. Zool. Soc. 



London, 1892, p. 50. 



