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VII, On the Stnicture of the Skull in the Chameleons. 

 By W. K. Pakker, F.R.S., F.Z.S. 



Eeceived March loth, 1880. 



[Plates XV.-XIX.] 



IjESIDES specimens in my collection of full-giown Chameleons of the common kind 

 and one of the dwarf kind (C. jiumilus), I received, some years since, a new-born young 

 one of the common species from my friend Mr. T. J. Moore, of Liverpool. 



This gave me an opportunity of comparing an early condition of this strangely formed 

 skull with its permanent form ; and the comparison of the two stages gave me the most 

 unexpected results : I found that the conception 1 had formed of the high, posterior 

 part of the skull, by comparison of it with the same parts in other Lizards, was as wrong 

 as could well be, and that my interpretation of these coalesced and highly modified 

 parts was worth as much as all guesswoik is worth, viz. worse than nothing. 



Having found my " key," I shall use it carefully in opening the meaning of this, the 

 most singular of all skulls. I shall describe the adult skull first, being confident now 

 of its true meaning ; and of it I shall take the outworks first and the inner building 

 afterwards. Then the skull of the young will be described, and its conformity and 

 nonconformity to other and more typical kinds of Lacertilian skulls shown. 



After that the dwarf kind will yield its less aberrant skull, to show that there is 

 nothing absolutely unchangeable in any type of skull, but that the more striking modi- 

 fications of structure are mobile as it were, and are always ready to oscillate this way 

 and that towards other morphological types and patterns. 



Nothing is easier than to speak glibly of generalized types and of types that are spe- 

 cialized ; in practice, however, no such facility is possible. Here is a family of Lizards 

 whose whole construction is special and aberrant to a marvellous and almost unique 

 degree ; and yet these very types are the most archaic, the lowest, and the most 

 generalized, in many respects, of all the known Lacertilia. 



.So much so is this the case, that every zoologist or anatomist describing the Lizards, 

 as a group, and giving their zoological and morphological characters, would have to 

 qualify one half of his description by repeatedly saying, " except in the Chameleons." 



I have long ago shown how remarkably this type differs from the other Lizards in its 

 VOL. XI.— p.i^BT in. No. 4. — March, 1881. o 



