THE LIZARD. ijr 



well to make a longitudinal vertical section of it 

 with a fret-saw. In the other skeleton the bones 

 should be disarticulated, the vertebrae being strung 

 on a string or wire, as separated, so as not to 

 disturb their order, and the other bones placed 

 out in proper position on a card : the skull 

 should be boiled for ^ to |^ an hour, and its con- 

 stituent bones gently pulled apart. This second 

 skeleton will of course bear more prolonged macera- 

 tion or boiling than the first or " natural " skeleton- 

 In both cases the hyoidean apparatus (§ 79-83 

 Figs. 39-40), must be dissected out with great care, 

 as it partly consists of delicate cartilages : con- 

 siderable care is also required in cleaning the 

 sternal ribs (§ 23). For the study of the chondro. 

 cranium a specially prepared skull is necessary : 

 (see§ VI. p. 143.) 

 II. Observe the general composition of the skeleton 

 as follows : 



1. The vertebral column, consisting of numerous 

 separate vertebra, divisible into (a) a cervical region 

 of eight vertebrae, forming the skeleton of the neck ; {b) a 

 thoracico-lumbar region of twenty-two vertebrae, forming, 

 with the ribs and sternum, the skeleton of the trunk : (<r) a 

 sacral region of two vertebrae, giving attachment to the 

 pelvis : and {d) a caudal region, consisting of a variable 

 number of vertebrae supporting the tail. 



2. The skull, articulated to the first cervical vertebra, 

 and consisting of (a) the brain-case and upper-jaw : 

 (b) lower-jaw, composed of two separate rami : and (<r) 

 the hyoidean apparatus supporting the tongue. 



3. The ribs, springing in pairs from many of the vertebra : 

 they become marked in the posterior cervical region, attaiq 



K 2 



