Atigust 4, 1881] 



NATURE 



311 



The chameleon's internal ear however is not an ex- 

 ceptionally perfect organ like its eye. On the contrary, 

 an important part, resembling a snail's shell in form, called 

 the cochlea, which is largely developed in us, and which 

 exists in a rudimentary manner in lizards generally, is 

 absolutely and entirely wanting in the chameleon.' 



The tongue of this animal is the most wonderful of all 

 its organs, and the chamajleon's entire organisation may 

 be said to have been formed with reference to this most 

 remarkable tongue. 



If the animal's mouth be opened, its tongue will be 

 seen as a thick fleshy mass lying between the two sides 

 of the lower jaw. At the front end of this tongue is a 

 cup-like depression with a prominence specially developed 

 above and below it like an upper and lower lip. But this 

 thick portion of the tongue thus at first vi>ible is but a part 

 of the entire structure. At its hinder end it suddenly nar- 

 rows into another very long and cylindrical part, which is 

 arranged and bent in transverse folds behind and beneath 

 the thick part first described. This narrow part or, 

 as it is called, " worm," finally bends to the front end of 

 the lower jaw, where it becomes continuous with a third 

 firmer part, which is rigid, because it contains a solid 

 body within. This third part reaches from the front of 

 the lower jaw to the back of the floor of the mouth, where 

 it enters a sort of funnel-like depression, to the bottom of 

 which it is firmly attached by flesh and membrane. The 

 cavity of the mouth is very deep, as is necessary for the 

 reception within it of this very voluminous tongue. When 

 the tongue is elongated it may be extended six or seven 

 inches. The action of the tongue will be spoken of in 

 connection with what I have to say as to the other actions 

 of the chama;leon. 



The structure of the chama;leon's feet is very note- 

 worthy. Each foot is (as has been said) practically a 

 pair of pincers, but each branch of each pincer is made 

 up either of two or of three toes bound together by the 

 skin down to the very roots of the claws. 



There are five toes or (as they are technically termed 

 in anatomy) " digits " to each foot, and these five digits 

 correspond with our own thumb and four fingers and our 

 own five toes respectively. 



In the fore-paw or hand of the chamaelcon the digits 

 which answer to our thumb, index, and middle digits are 

 bound together in one bundle, while the digits answering 

 to our ring and little fingers form the other bundle. 



In the hind-paw or foot of the chamsleon the arrange- 

 ment is different. There the digits which answer to our 

 great and second toes are bound together in one bundle, 

 and rre opposed to another bundle formed of the third, 

 fourth, and fifth toes. 



Moreover while the three united digits of the fore-limb 

 are directed inwards, the three united digits of the hind- 

 limb are directed outwards. 



There is yet another noteworthy point as to the struc- 

 ture of the paws. In ourselves the small bones which 

 form our "wrist'' and our "ankle" respectively are (as 

 they are in almost all beasts) distinct and separate from 

 those long, more or less slender bones which are in the 

 palm of the hand and the sole of the foot, and which are 

 called "metacarpal bones" in the hand and "metatarsal 

 bones " in the foot. In the chama-leon however each 

 metacarpal and each metatarsal absolutely unites with 

 the wrist or ankle bone which is adjacent to it, so that 

 they together form but one bone. 



As to the internal organs of the chamreleon, I will only 

 speak of the lungs. These organs are practically a pair 

 of bags — air-bags — but each bag is furnished with seven 

 or eight tubular prolongations, which seem each to end in 

 a point. These ends however really open into certain 

 sacs within the cavity of the body, which sacs can thus be 

 inflated and the whole body much blown out. 



^ See Prof. Parker's pap^r in the Ttansaitions of the Zool. Soc, vol. 



The last structure I shall notice is the skin, so remark- 

 able for the very conspicuous changes of colour it under- 

 goes. The chamaeleon's skin, like the skin of other 

 animals, is furnished with very minute bags containing 

 pigment. It is the presence of very many such bags con- 

 taining a dark pigment which makes the negro's skin 

 black. These pigment-bags are called " chromatophcres," 

 and the chromatophores of the cham.-eleon, unlike those 

 of the negro, are contractile, and it is by the alternate 

 contraction and expansion of chromatophores containing 

 different coloured pigments that the changes of colour 

 which take place in the chamasleon's skin appear to be 

 effected. 



The chamreleon does not make at all a bad pet. It is 

 not only perfectly inoffensive, but most gentle and not at 

 all wild, while it forms an object very interesting to con- 

 template. It needs to be kept warm and supplied with 

 flies, mealworms, or other insects, and also with water, 

 and with some branching shrub on which it may perch 

 and climb. It is better to inclose the shrub in a glass case 

 or cage, to prevent such accidents as happened to one of 

 mine, which, being left alone and free, wandered to the 

 fire-place, where it got beneath the grate, and so 

 scorched its paws that it could no longer climb, and soon 

 died. 



Wonderful is the slowness with which the chamaeleon 

 ordinarily moves. When at rest it clings to the branches 

 by its four paws and prehensile tail. When it wishes to 

 advance it only moves one limb at a time. Let us say it 

 begins by moving the right fore-limb. It first, of course, 

 unhooks that paw, and then, bending the ellaow, slowly 

 raises it and holds it suspended a certain time, moving it 

 right and left, forwards and backwards, till it finds a suit- 

 able foothold. Then its pincer-like fingers slowly and 

 firmly grasp the new point of support, after which the left 

 hind-limb performs a similar series of movements ; then 

 follows the left fore-limb, afterwards the right hind-limb, 

 and finally the tail is unrolled, and then readjusted round 

 some new sustaining object. 



This is its ordinary mode of progress, but it can sus- 

 tain itself by its tail only, and when thus hanging may 

 seek for fresh foothold by stretching in various directions 

 all its four limbs. 



The chamreleon is probably the most thoroughly 

 arboreal animal which exists. Many creatures of dificrent 

 kinds -which live in trees are furnished with a prehensile 

 tail. This is the case, for example, with the most arboreal 

 monkeys, such as the spider- and howling-monkeys. It 

 is also the case with that most arboreal member of the 

 raccoon family, the kinkajou, and with the most arboreal 

 'members of the porcupine family and of the opossum 

 order. 



Arboreal animals may have their feet especially or- 

 ganised for climbing, as is the case with monkeys and 

 opossums, but they are not such perfectly and exclusively 

 climbing organs as are the chamaeleon's feet. The sloths 

 are animals the whole organisation of which is planned for 

 tree-life, and their paws are modified to serve almost 

 exclusively for climbing, and their digits are also bound 

 together by skin to the roots of the claws. Moreover, in 

 the sloths the wrist and ankle bones may more or less 

 coalesce with the metacarpals and metatarsals, as in the 

 chameleon ; nevertheless the sloth's digits are not 

 pincers, but hooks only, all the digits of each foot being 

 bound together in a single bundle. Moreover, admirable 

 as is generally the arboreal organisation of the sloth, that 

 animal is nevertheless devoid of a prehensile tail. 



In birds the ai kle-bones coalesce with the metatarsals, 

 and there is a certain resemblance between the feet of 

 the climbing arboreal parrots and those of the chamajleon, 

 for though the parrot's toes are not bound together to the 

 claws, they yet form a pair of pincers, two of them being 

 turned in one direction and opposed to the other two 

 Yet the mode in which they are grouped is different, for 



