325 



Measurements of thirty-four skulls O/LYNX RUFUS et vars. 



PEOCYON LOTOE. 



The present species presents another well-marked case of gradual in- 

 crease in size southward. In a series of fifteen skulls from the Atlantic 

 States (New York, Pennsylvania, and Georgia), only a single specimen 

 exceeds 4.38 in length or 3.00 in width, the largest specimen being from 

 Saint Simon's Island, Georgia. Three from Essex County, New York, 

 average 4.28 ; five from Pennsylvania average 4.29 ; seven from Saint 

 Simon's Island, Georgia, average 4.26 (or 4.29, excluding one very small 

 one). Six specimens from the interior (Nebraska, Missouri, Indian Ter- 

 ritory, and the Lower Eio Grande) average 4.49, two only falling below 

 4.50^ and the largest (Eio Grande) 4.70. Three from California ("hernan- 

 dezi") average 4.63, the largest reaching 4.78, with a width of 3.38. Six 

 from Southern Mexico average 4.58, the largest reaching 4.73 in length, 

 with a width of 3.42. Three from Costa ,Eica average 4.69, the largest 

 reaching 4.85. 



In addition to the above, there is a single very aged specimen from 

 Detroit, Mich., which has a length of 4.35, and two others from Alaska 

 (one middle-aged, the other rather young) which measure, respectively, 

 4.25 and 4.05 in length, the latter being the smallest of the whole series, 

 although it contains others equally young. 



Between the three specimens from Essex County, New York, and the 

 three from Costa Eica, specimens of corresponding ages and constitut- 

 ing the two extremes, the average difference is nearly six-tenths (0.57) of 

 an inch, or about one-seventh of the size of the northern examples. 



Besides the difference in size, there is also a considerable range of 

 variation in respect to the general form of the skull in the ratio of width 

 to length, in the shape, degree of concavity of the palate, in specimens 



