Iguanas are often brought to the markets, either lashed lengthwise to a branch of the tree on which the specimen happened to be surprised, or tied up with the long tendons of their own toes.
Fig. 132.–Iguana tuberculata. × ⅕.
Metopoceros cornutus of Hayti is closely allied to Iguana, but the male has three conical horn-like scales on its head. The general colour of the whole animal, which grows to more than one yard in length, is dull black.
The following two genera, each containing one species only, are restricted to the Galapagos Islands. Darwin[[160]] gives a long and vividly written account of their habits.
Conolophus subcristatus.–Fully grown specimens are a yard long. Their shape is stout, the head and fore part of the body appearing especially heavy. The head is covered, or rather paved, with large cobble-stone-like scales. On the neck is a low crest of recurved spines, while the median line of the back appears simply serrated. All the teeth are trilobate. A gular sac is absent. The coloration is striking. The head is lemon-yellow; the back is red, merging into dark brown on the flanks. The belly is dark yellow with a tinge of reddish brown.
This lizard was found by Darwin on some of the Galapagos Islands. On James' Island it was so common that the party found it difficult to pitch their tent, on account of the ground being undermined by the many burrows of the reptiles. They feed during the daytime upon the succulent cactus and the leaves of various trees. The perfectly harmless creatures are, or were, eaten by the inhabitants.
Amblyrhynchus cristatus is closely allied to Conolophus, of which it may be said to be an aquatic modification. The top of the blunt head is covered with low, conical, broad-based scales. Over the neck, back, and tail extends a continuous crest of low, recurved, spiny scales. All the teeth are trilobate. The body and even more so the tail are laterally compressed. The general colour is dark brown above, paler and inclining to whitish below. Younger specimens have pale grey spots and blackish cross-bands on the back and sides. Total length up to 4 feet. The remarkable feature of this Iguanoid is its semi-marine life. It inhabits the rocky and sandy strips of coast of most of the Galapagos Islands, feeding upon certain kinds of algae, which it has to dive for, since these plants grow below tide-marks.
Phrynosoma ("Horned Toads").–The body of these little creatures is much flattened and broadened, devoid of a dorsal crest, but covered with larger and smaller, strongly keeled scales. The head is bordered posteriorly by conspicuous osseous spines. The under parts are covered with small, very regular scales. Both sexes have a long row of pores on the under surface of the thighs. The general colour of the upper parts is a mixture of yellow, grey, brown, and black, the larger spiny scales causing the animal to look as if it were sprinkled with the dried husks of seeds, for instance those of Buckwheat. The object is concealment, by close adaptation to the arid, sandy localities which are the home of "Horned Toads." About one dozen species inhabit the western half of the United States and Central America. All the species are viviparous, almost the only instance among Iguanidae.
Ph. cornutum has five spikes on each side of the head: one postorbital, three temporal, and one occipital, the latter being by far the largest. The sides of the lower jaw project in the shape of prominent ledges, and are protected by a series of small spines. The ventral scales are keeled. The under parts are yellowish, frequently with a few brown spots. This species, which grows to a length of 5 inches, ranges from Illinois through Kansas and Texas to Northern Mexico.