450 ME. M. r. WOOBWABD ON MAMMALIAN DENTITION. [May 2, 



3. Contributions to the Study o£ Mammalian Dentition. — 

 Part I. On the Development of the Teeth of the Macro- 

 podidse. By M. F. WoodwarDj Demonstrator of Zoology, 

 Royal College of Science^ London. (Communicated by 

 Prof. Howes.) 



[Eeceived May 2, 1893.] 

 (Plates XXXV.-XXXYII.) 



Contents. 



I. Historical Review, p. 450. 



II. Observations on the Specimens, p. 451. 



III. General Considerations, p. 465. 



IV. List of Eeferences, p. 471. 



V. Explanation of the Plates, p. 472. 



Early in 1892 I had placed at my disposal, through the kindness 

 of Prof. Howes, a number of fcetal mammals of various kinds, 

 -which were for the most part derived from the late Prof. W. K. 

 Parker's collection. I have been for some time past investigating 

 these specimens and now submit a few of my results in this 

 contribution. 



I. — HlSTOEICAl EeVIEW. 



Since Kiikenthal (4) published his preliminary observations 

 on the development of the teeth of the Cetacea and of Didelphys, 

 an entire revision of the science of Odontology has been necessi- 

 tated. This has been taken up eagerly by many Continental 

 observers, notably Leche, Eose, and Taecher, so that notwithstand- 

 ing the newness of the study there is already springing up a rapidly 

 increasing literature. 



Most, however, of these observers have confined their attention 

 to a few isolated examples, and no systematic examination and 

 comparison of the tooth relationships in the various orders of 

 Mammals, such as that commenced by Pouchet and Chabrys (9), 

 has been attempted. 



In dealing with the Marsupials these observers have mainly 

 studied the tooth relationships of Didelphys, Kiikenthal (5) and 

 Eose (9) having made most exhaustive investigations of this genus. 



Eose has further published some interesting but largely theo- 

 retical views of the tooth development in Acrohates, Dasyurus, 

 Fhalangista, and Macropus ; while Leche (6) has published pre- 

 liminary accounts of that of Phascolarctos, Perameles, Myrmecohivbs, 

 and Trichosurus. 



The only investigation which treats of the facts dealt with in 

 this paper is that of Eose (9) on Macropus ; he, however, only 

 devotes a few lines to his observations, which were based on 



