THE POSTERIOR LIMBS. 107 



fibula is also as long as the tibia, and is united to that bone at three points : at the two 

 extremities by articular surfaces, in the inferior third and middle by an interosseous 

 ligament. 



D. POSTERIOR FOOT. 1. Bonts of the tarsus. The number of tarsal bones varies a 

 little in the domesticated animals, as the following list will show : 



Carnivora and Pig 7 



Ox, Sheep, and Goat 5 



In the Dog, Cat, and Pig, there are three cuneiform bones, and in the Ox and Sheep, 

 in addition to there being only two cuneiforms, the scaphoid and cuboid bones are < on- 

 solidated into one piece. 



The astragalus of the carnivora articulates with the scaphoid by means of a veritable 

 head, separated from the rest of the bone by a constriction termed the n< ck of the astra- 

 galus. The cuboid and the cuneiform bones respond to all the metatarsals. 



In the Pig, the astragalus and calcaneus are very long. The cuneiforms and cuboid 

 respond to the four perfect digits. 



The tarsus of the domesticated Ruminants is slender above. The astragalus is elongated 

 from above to below, and is united to the scaphoid by an antero-posterior groove, and to 

 the calcaneus by a more superficial vertical groove. The calcaneus is long and ti.in; 

 the posterior gliding surface on the summit is excavated into a channel ; the small 

 cuneiform is pisiform and but slightly developed. 



2. Bones of the metatarsus. The metatarsus is also a region in which the number of 

 bones varies in the domesticated animals. Thus in the Carnivora and Pig there are 

 five, and only two in RUMINANTS. 



The metatarsals of the Carnivora and Pig are exactly like the same bones in the 

 anterior limb. Those of Ruminants are slightly different. 



In the Dog and Cat are one rudimentary and four perfect metatarsals. The former 

 is articulated with the internal cuneiform, and represents the vestige of the thumb. 



The Pig has four perfect metatarsals, and an internal rudimentary one. The latter 

 is a small bone flattened on both sides, articulating by means of a diarthrodial facet, and 

 sometimes consolidated behind the upper end of the fourth metatarsal. 



In the Ox, Sheep, and Goat, is found a principal and a rudimentary metatarsal bone. 

 The latter is like the rudimentary metacarpal bone , but the former differs from the 

 principal metacarpal bone in being longer, quadrilateral in form, and having a vascular 

 canal traversing the posterior face of its upper extremity. 



3. Bones of the digital region. In all the domesticated animals, the posterior digits 

 comport themselves exactly like the anterior. The Carnivora alone offer a notable differ- 

 ence; in them, in reality, the thumb does not exist, or rather, it is only represented by 

 the rudimentary metatarsal bone alluded to above. Nevertheless, it frequently occurs 

 that a completely developed thumb is found in this animal ; and in this case the rudi- 

 mentary metatarsal is ordinarily followed by a ligamentous cord, to which is suspend< d a 

 bony stylet that represents either the inferior extremity of the metatarsal, or the first 

 phalanx ; it is to this stylet that are found articulated in succession the second and third 

 phalanges. 



(Professor Fuchs, of Carlsruhe, found, in a Newfoundland dog, four true claws and 

 two false : the internal of the latter corresponded to a well-developed, small metatarsal 

 bone, while the external was only rudimentary, terminating in a point, and bound to the 

 tarsus by a simple ligament.) 



COMPARISON OF THE ABDOMINAL LIMB OF MAN WITH THAT OF ANIMALS. 



A. PELVIS. The longitudinal axis of the pelvis of Man forms, with the horizon, an 

 angle of about 40. 



The bones which compose it are proportionately larger and stronger t' an in all the 

 domesticated animals. 



The two faces of the ilium, and especially the inner face, are much hollowed ; the 

 iliac crest has the form of an italic 8. 



The pubis alone participates in the formation of the pelvic symphysis, and I he con- 

 cavity which, in the domesticated animals, is called the isi-hial arch, id designated in Man 

 the pubic arch. 



In consequence of the excavation on the inner face of the ilium, the pelvic cavity 

 may be divided into the great and lesser pelvis In the latter are lodged the genital 

 and urinary organs, as well as the extremity < f tho d'g^th e tube. 



J3. THIGH. The femur of Man is nearly vertical, and situated in a direction slightly 



