144 



tail is long and prehensile, but all the vertebrae are not preserved in this skeleton. The sca- 

 pular arch consists of long, slender, rib-like scapulae overlapping the first pair of ribs, and 

 of broad, semiossified coracoids which articulate with a rhomboidal semiossified manubrium 

 sterni. The pelvic arch is completed by two pubic bones anteriorly, which are distinct from 

 the two more slender ischia. The bones of the extremities are long and slender : the digits 

 are especially arranged for grasping ; three internal ones are opposed to two external in the 

 fore-foot, and three external are opposed to two internal digits in the hind-foot. 



Purchased. 



665. The skeleton of the bifurcate or two-homed Chameleon (Chamceleo bifurcatus). 



The name is derived from the two long and strong compressed and rough processes of 

 bone, continued forwards, slightly diverging, from the anterior part of the skull, formed by 

 the prefrontal, nasal and maxillary bones. The number of vertebrae which support moveable 

 ribs is 15. Two vertebrae without ribs represent the lumbar series, and the three following 

 combine to support the pelvic arch, and in that respect may be regarded as sacral. The 

 spinous processes are remarkable for their length and strength in this species. The zygapo- 

 physes are also continued upwards and outwards like transverse processes ; the true diapo- 

 physes are short and simple convex tubercles, as in other Lizards, and exclusively support 

 the ribs. 



Presented by Dr. Leach, F.L.8. 



Family Iguania. 



Genus Iguana. 



666. The skeleton of an Iguana (Iguana tuber culatd). 



The teeth are anchylosed to the inner side of the outer wall or rampart of an open alveolar 

 groove ; their crowns are expanded, compressed, pointed, with finely serrated margins. There 

 are 25 teeth in the upper jaw, and the length of this range is 1 inch ths. Twenty-one ver- 

 tebrae support free ribs, which commence at the fifth. The first four pairs are simple and 

 floating, progressively increasing in length. The pleurapophyses of the ninth vertebra are 

 first joined to the sternum by slender semiossified haemapophyses. The three succeeding pairs 

 are similarly joined to the sternum. The next three pairs are united by a common cartilage to 

 the end of the expanded part of the sternum : the remaining pairs of ribs are again free or 

 floating, and progressively diminish to the twenty-fourth vertebra. The pleurapophyses of 

 the twenty-fifth and twenty-sixth vertebrae are much thickened and anchylosed : the extremity 

 of the twenty-fifth is grooved or notched ; these two vertebrae support the pelvic arch and 

 form the sacrum. The anchylosed pleurapophyses in the anterior caudal vertebrae are simple, 

 straight, depressed, and represent long transverse processes, but they progressively diminish 

 in length and disappear at the forty-sixth vertebra. The haemapophyses begin to be developed 

 at the second caudal vertebra ; they coalesce at the extremities and form a haemal spine, but 

 they remain free from the centrum, and are articulated both to the vertebra to which they 



