440 LOWER VERTEBRATES. 



E. shUtonianum, Skilton's skink, inhabits tlie Pacific region, and has the body 

 greatly elongated, the tail, wliich is more subquadrangular than conical, being about 

 twice the length of the body. The limbs are small, and the scales, though elsewhere 

 smooth, on the back and tail present four or more longitudinal furrows or stripes. 

 E. anthracinus is found in the more mountainous regions from Pennsylvania to Texas. 

 E. egregius and onocrepis inhabit Florida. In the more southwestern territories are 

 several other species. The eggs of this genus are laid, to the number of ten or a 

 dozen, under leaves, stones, or the bark of trees. 



The family Axelyteopid^ includes a small number of degraded skinks. Tijphline 

 has no limbs, and the pre-anal shield large and single. The eyes can be faintly dis- 

 cerned through the covering of skiji. Specimens have been taken at the Cape of 

 Good Hope. Feylinia is also unprovided with limbs, but has the j) re-anal scales nu- 

 merous. It inhabits the coast of Africa in the neighborhood of Angora. 



This family includes, under the head of Dibamid.e, a still more degraded genus, 

 Dibamus, which has none of the osteological peculiarities which characterize the pre- 

 vious families. The posterior limbs only are represented, and these by mere folds 

 of skin. The pre-anal scales are undifferentiated. Its home is New Guinea. 



The members of the highest family, the Ciiam.eleontid^, are all natives of 

 the Old World, and are characterized by having the tongue worm-like, club-shaped, 

 in front, and very exsertile. But a single genus, the acrodont Chmneleo., is repre- 

 sented. 



The chameleons have the large and angular head covered with small, flat shields; 

 the deep and compressed body with shagreen-like skin, and the tail, characteristic, 

 long and prehensile. The eyes are large and globular, and each can be directed towards 

 an object of its own : the eyelids are circular and pierced by a central hole ; the 

 tympanum is hidden, and the limbs, which are perhaps the most specialized organs of a 

 highly sjjecialized animal, are capable of supporting the body, and terminated by feet, 

 which are converted into grasping hands by having the five toes arranged by their 

 imion as far as the claws in two opjjosing groups. With the strong grasp of tlieir feet 

 and with the assistance of the prehensile tail, it is almost impossible to shake them off 

 the branch on which they may be slowly feeling their way. On the ground or in the 

 Avater they are almost helpless. The eggs, protected by a calcareous shell, are de- 

 posited, to the number of ten or twelve, under decaying leaves. 



The singular power of changing the color of skin is not .alone possessed by the 

 members of this family, nearly all of the lacertilians having it to a more or less 

 degree. The i^henomenon is brought about by there being two layers of jiigment 

 cells underlying the transparent epidermis, the lower and darker, at the will of the 

 animal, or stimulated by surrounding objects, predominating over and through the 

 more superficial and lighter layer. Though the proper home of the chameleons is 

 Africa, where there are several species, they are found along the northern shores of 

 the Mediterranean, in Asia, and on the island of Madagascar. 



Order IV. — CHELONIA. 



The members of this order present less variation in form than do those of any 

 other of the class. The body is invariably short and stout, and is, in all the known 

 forms, ]n-otected from above and below by a more or less bony investment, developed 

 ordinarily, directly from the osseous framework ; though some forms may have this 



