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THE POPULAR SCIENCE MONTHLY. 



styloid process is itself prolonged down to the tongue-bone and artic- 

 ulated with it in the fresh state. It is quite a large bone, three 

 and a half inches long (see Fig. 1, A). This arrangement is seen in 

 many of the lower animals, and in them the bone, which is a very 

 important one, is called the epihyal hone. 



2. At the base of the skull on the left side, behind the mastoid 

 process, the prominent nipple-shaped process behind the ear, is a stout, 

 bony spur, more than three quarters of an inch long, which has a 

 downward direction, and articulates with the first bone of the ver- 

 tebral column (see Fig. 1, J5). This process is rarely seen in the 

 human being, and is the only one I have met with, but it is quite the 

 normal condition in most graminivorous and carnivorous animals, 

 being especially well marked in the horse, pig, sheep, and goat. In 

 them it is an important part, and gives attachment to strong muscles 

 which move the head on the trunk. It is called the para-mastoid 

 process, from its proximity to the mastoid. 



SuPERNUMEEARY RiBs. — I suppose cvcry one is aware that the 

 vertebral column, or backbone, is composed of many separate bones, 

 some of which carry ribs. The backbone is made uji of thirty-three 

 bones, seven in the neck, twelve in the trunk, five in the loins ; below 

 this we have a bone called the sacrum, which consists of five vertebrae 

 fused together ; and lower down still four small bones which represent 

 the tail-bones, called, when taken together, the coccyx, from their 



Fig. 2.— C C, cervical ribs ; T, transvers process of seventh cervical vertebra. 



supposed resemblance to a cuckoo's beak. Now, each trunk, or dorsal 

 vertebra, has two ribs connected with it, one on each side ; so there 

 are altogether twenty-four ribs, twelve on each side ; but sometimes 



