THE IGUANOID LIZARDS 2501 



partiality for water, although, on occasion, they can swim as well as the true 

 iguanas. They feed mainly or entirely on grass, and when disturbed in grazing, 

 these reptiles rush back to the trees with extraordinary speed, sometimes taking 

 great leaps like a frog, although their movements are generally deliberate and slow. 

 If unable to escape, they show fight in much the same way as the true iguanas. 

 The breeding habits of this species do not appear to be known, although the females 

 of the allied black iguana {Ctenosaura acanthura) of California are in the habit of 

 laying in company, like the true iguanas. The ring-tailed iguana exhales a 

 peculiarly disagreeable smell, which is stated to be so objectionable as to cause even 

 the ants to forsake a room into which one of these creatures is brought. For 

 this reason its flesh is uneatable, although that of the black iguana is highly 

 esteemed. 



We have not hitherto mentioned that the vertebrae of the iguanoid 



lizards differ from those of the agamoids and most other members of 

 Iguanas 



the suborder in being furnished with additional articular facets like 



those of snakes. Vertebras of this peculiar type occur in the upper Eocene rocks 

 of England and the Continent, and have been provisionally assigned to the typical 

 genus Iguana, although it is more likely that they indicate an extinct genus. 

 Somewhat similar vertebrae from the corresponding strata of the United States 

 have been described under the name of Iguanavus. 



The last and at the same time the most peculiar members of the 

 or ^ e . present family are the horned lizards of North America and Mexico, 



which may be regarded as the representatives of the moloch lizard 

 among the agamoids. From their short, rounded heads, abbreviated bodies, and 

 shortened tails, coupled with a general batrachian appearance, these lizards are 

 commonly termed toads in America, the popular name of the figured species 

 (Phrynosoma cornutum) being the Californian toad. Strange, not to say ugly, in 

 appearance, these lizards are at once distinguished from all their allies by the pres- 

 ence of several bony spines projecting from the back of the shortened head, and of 

 tubercles or spines scattered among the ordinary scales of the body. In form, the 

 body is broad and depressed, without any crest down the back; and the tail is very 

 thick at the base and never longer than the body. The limbs are rather long, with 

 pores on the thighs, and keeled plates on the lower surfaces of the toes. From 

 most other members of the family these lizards are further distinguished by the 

 absence of teeth on the palate. Of the twelve species of the genus the best known 

 is the common horned toad, herewith figured, which has the tail longer than the 

 head, distinct spines on the back, and the drum of the ear naked. Its general 

 appearance is even more than superficially toad-like, the head being as broad as 

 long, and the body being remarkable for its extreme plumpness. Measuring a little 

 over five inches in length, this species is rather handsomely colored. Above, the 

 ground color is grayish or brownish, with a more or less well-marked light stripe 

 down the back, and dark brown spots at the bases of the larger spines; there are like- 

 wise markings of the same color on the nape and head. Beneath, the hue is 

 yellowish, with or without a few small brown spots. In two species of the genus 

 (e. g. P. taurus) the tail does not exceed the head in length. The common species 



