2 1 8 Bulletin American Museum of Natural History. [Vol. XXII, 



Note. In the foregoing table the Museum number followed by N (<?. g., 

 6480 N) indicates that specimens thus indicated are in the U. S. National 

 Museum. In like manner, 3674 F indicates that the specimen is in the Field 

 Columbian Museum. All other numbers refer to specimens in the American 

 Museum of Natural History. The measurements of the National Museum 

 specimens of Mexican Jaguars are compiled from those given by Dr. Mearns 

 (Proc. Biol. Soc. Wash., XIV, 1901, pp. 137-153). The measurements of the 

 rive National Museum specimens from South America were taken by myself, 

 the specimens having been kindly loaned to me for examination by the author- 

 ities of the National Museum, through Mr. Gerrit S. Miller, Jr., Assistant 

 Curator, ^Division of Mammals. 



The method employed in taking the above measurements needs no expla- 

 nation, further than to say that 'basal length' is the basal length of Hensel; 

 and to add that 'length of palate' and 'foramen magnum to palate' are taken 

 not from the median palatal notch, nor from the points bordering the notch, 

 but from that portion of the posterior border between these points and the 

 lateral wall of the interpterygoid fossa. The form of the posterior border 

 of the palate varies individually and with age; usually there is a median V- 

 shaped notch that penetrates more or less deeply into the border; on each side 

 of the notch the border is produced posteriori}'' into a more or less long, spine - 

 like process, between which and the lateral margin of the bony palate the 

 border may be either slightly or deeply hollowed, and it is from this part of 

 the border that the two above-mentioned measurements are taken. In young 

 and middle-aged specimens, the median notch and the lateral hollows are usually 

 deeper than in very old specimens, in which they have been filled out, more 

 or less according to the individual, by the gradual deposition of bony matter 

 at the posterior border of the palate with increase of age. 



The basal length varies in 7 old males from Mexico from 187 to 

 220 mm., with 2 Costa Rica specimens at, respectively, 200 and 212; 

 3 Paraguay and Bolivia specimens range from 203 to 212, with a 

 fourth at 242 ; other adult to old specimens (sex unknown) are 

 somewhat smaller. 



The width of the interpterygoid fossa varies in 6 Mexican speci- 

 mens from 20 to 23, averaging 21.4; while the same measurement in 

 5 specimens from southern South America ranges from 25 to 29, 

 averaging 27.4. The basal length of the skull in these two series is, 

 respectively, 200 and 214, -the variation being quite out of pro- 

 portion to that of the width of the interpterygoid fossa. The dentition 

 is appreciably heavier in the South American skulls, pm^ averaging 

 i mm. , and the combined length of pm 2 and pm 3 averaging about 

 2.5 mm. greater. These cranial and dental differences, combined with 

 the deeper, richer colors of the South American animal, satisfactorily 

 show that the South American Felis onca and the North American 

 F. hernandezii may be regarded as specifically separable. 



