162 ANATOMY OF THE WOOD RAT 



an unknown extent, but some such standard must be taken 

 in the present work. When mentioned hereafter, the term 

 functional length of leg, therefore, comprises the sum of 

 lengths of femur, of the tibia, and half the distance from the 

 heel to the end of the longest metatarsal. Unfortunately, 

 but two of the skeletons of Homodontomys, three of Neotoma 

 and two of Teonoma, were accompanied by articulated feet, 

 so that this detail could be calculated for but this number. 

 The functional length of the hind leg, as calculated by 

 the above formula, varies from 64.7 to 68.2 per cent of the 

 length of the body vertebrae in Homodontomys; from 74 to 

 78 in Neotoma; and from 72 to 75 per cent in Teonoma. In 

 Homodontomys it is from 31.7 to 34 per cent longer than 

 the functional length of the fore limb; in Neotoma, from 

 33.4 to 34.8 per cent, and in Teonoma, 36 per cent. 



Thigh 



Femur. The femur or thigh bone has a length in Homo- 

 dontomys of from 41.7 to 42.4 per cent of the functional 

 length of the leg; in Neotoma from 41.7 to 42.3 per cent; 

 and in Teonoma, 43.2 per cent. (In N. f. ruhida the average 

 is 40.8 per cent.) 



Upon the medial side of the proximal end of the femur is 

 situated the circular head, articulating with the acetabulum. 

 It is connected with the shaft by a constricted neck, and has 

 a depression upon the medial aspect of its circumference 

 for the reception of the ligamentum teres. The great tro- 

 chanter is located laterad to the head and is a continuation 

 of, and in direct line with, the shaft. It projects from one 

 to two milhmeters proximad of the head. Upon its lateral 

 surface is inserted the gluteus minimus, gemellus superior, 

 and gluteus medius, and upon its caudal border, termed the 

 intertrochanteric line, a portion of the gluteus maximus. 

 Upon its cranial portion, constituting the proximal termina- 

 tion of the lateral ridge of the femur, originate the vastus 



