74 ELEMENTS OF MAMMALIAN ANATOMY 



1 7. Describe the condition of the bones of forearm in the horse and its ancestors. 



18. In a five-month fetus of the horse the ulna is distinct from radius and 

 complete, while in the mature animal but little more than the distal third re- 

 mains, and is anchylosed to the radius. Explain significance of this fact. 



19. Draw ventral aspect of carpus and label all parts. 



20. Wherein is the chief difference between carpus of cat and man? 



21. Draw the lateral aspect of the third metacarpal and label all features. 



22. How do you distinguish the distal from the proximal end of the metacar- 

 pals? 



23. Describe the variation in the number of metacarpals in mammals. 



24. Describe the usual arrangement of the phalanges in mammals having five 

 digits. 



25. How do you distinguish a phalanx from a metacarpal? 



26. Give the number of functional digits in forelimb of dog, pig, cow, sheep, 

 horse, and rabbit. 



27. Name some mammals with atrophied digits. 



28. What is the significance of these? 



29. In the evolution of the perissodactyls (odd-toed ungulates) describe the 

 order in which the digits are lost. 



30. In the Bovidae and Cervidas which two digits are functional? 



THE PELVIC LIMB 



The pelvic or hind-limb of the cat is composed of the innomi- 

 nate bone, femur, patella, tibia, fibula, seven tarsals, five 

 metatarsals, and twelve phalanges. 



The coxal or hip bone is composed of four parts, the ilium, 

 ischium, pubis (Figs. 22 and 39), and the small acetabular or 

 cotyloid bone. The ilium is the dorsal portion, extending down 

 to and occupying about one-third of the acetabulum. The 

 ischium includes the caudal portion of the bone, extending ven- 

 tral and forming two-thirds of the boundary of the obturator 

 foramen. The pubis is the ventral portion, possessing two rami, 

 one projecting laterad to unite with the ilium, cotyloid, and 

 ischium, and the other projecting caudad along the mid-ventral 

 line, joining its fellow and the ischium. In young kittens the 

 junction of these parts is plainly visible, but in adult specimens 

 it is wholly obliterated. In old specimens the ischium and 

 pubis become more or less anchylosed with their fellows in the 

 mid-ventral line. The cranial and dorsal border of the ilium 

 is the crest (Fig. 40). The rough crescentic area on the medial 



