THE LIZARD. 131 



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 J 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 vertebrae, 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 : (f) a 

 sacral region of two vertebrae, giving attachment to the 

 pelvis : and (e) 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 (c) 

 the hyoidean apparatus supporting the tongue. 



3. The ribs, springing in pairs from many of the vertebrae r 

 they become marked in the posterior cervical region, attain 



K 2 



