THE DEVELOPMENT OF THE AXIAL VEINS 



AND LYMPHATICS IN TRAGULUS 



MEMINNA, ERXLEBEN 



FREDERICK TILNEY 

 From the Anatomical Laboratory, Columbia University 



FOURTEEN FIGURES 1 



MATERIAL 



The material on which this investigation is based consists 

 of five embryos of the ruminant ungulate, Tragulus meminna 

 (Indian Chevrotain) measuring 5mm., 6 mm., 13 mm., 20 mm. 

 and 23 mm. respectively. These were obtained by exchange 

 from the Smithsonian Institute through Dr. A. Hrdlicka. The 

 series represents the entire embryological material of this form 

 collected during a number of years in Borneo and adjacent 

 islands of the Malay Archipelago by Dr. Abbott of the Insti- 

 tution. 



In view of the very great importance of Tragulus to the phylo- 

 genetic interpretation of the marsupial and placental vascular 

 system, and of the probability that further embryos of this 

 animal will not soon again become available for study, it seems 

 advisable to publish the main results of the investigation based 

 on the material now in hand. This becomes all the more im- 

 perative since we possess the complete account of the develop- 

 ment of the postcava in embryos of Didelphis marsupialis fur- 

 nished by McClure ('03), and hence have the opportunity of 

 directly comparing the available series of Tragulus with the 

 corresponding marsupial stages. 



The two smaller (5 mm. and 6 ,mm) and the two larger (20 

 mm. and 23 mm.) embryos of Tragulus here described proved 

 to be admirably fixed and preserved and well adapted for minute 

 and detailed study. The intermediate embryo of 13 mm. is 

 in a less satisfactory condition and has hence only been used 



1 Expense of illustrations borne by author. 



193 



