396 



r/iOCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 49. 



Measurements. 



Dimensions taken. 



Width across the snout at nasal opening 



Ileigiit of skull behind orbit.s 



From rear of nostril to roar of nasal bones 



From rear of nostril to front of orbit 



Distance between inner borders of first molars 



Ratios. 



68 

 66 

 48 

 48 

 59 



While these measurements show a great difference in the sizes of 

 the two specimens, the ratios indicate considerable differences of 

 proportions. The variations observed can not be due to differences 

 of age; for, as shown by the more advanced condition of the hinder- 

 most molar, the Oregon specimen was the older. 



If now we take the distance from the rear of the nostril to the rear 

 of the nasal bones as a measm'e and give it the value 100 we shall 

 have the following table: 



Ratios of measurements. 



From these estimates it appears that relatively to the distance 

 from the nostril to the rear of the nasals,. D. hesperus has a wider 

 snout, a higher skull, and a narrower palate between the last molars 

 than the Japanese specimen had. 



Quito as important as regards the relationships of the two animals 

 is the structure of the first molar. There seems to have been in the 

 Oregon specimen only two columns in the anterior row, although it 

 is possible that a median one sprouted off from the base between the 

 two recognized; but behind this row is only one transverse row of 

 two columns; whereas, in the Japanese specimen, there were two 

 transverse rows of two columns each. 



The Oregon animal can hardly belong to anything else than the 

 species called by Marsh Desmostylus hesperus. Under the circum- 

 stances it is the Japanese species which must receive a name. Hence, 

 in honor of my friend Sliozaburo Watase, Professor of Zoology in the 

 Imperial University of Tokio, I caU it Desmostylus watasei. 



The following diagnoses may be proposed: 



