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Show 214 DR. H. GADOW ON MEXICAN [June 6, the Isthmus of Tehuantepec, and are restricted to Central America. Some species have a very wide, others a very limited distribution. The majority combine humivagous with climbing habits, and show great adaptiveness to the nature of their surroundings ; for instance, /S. scalaris and >$. (tineus do not climb the trees beneath which they live, but prefer the grassy ground, and they are equally at home in the moist, clouded pine-forests and on the more barren, grassy and lava-strewn slopes up to the snow-line. S. variabilis prefers the wooded lowlands of the Atlantic side, and likewise does not climb, loving the banks of rivulets and well-herbed ravines. Others, e. g. S. torquatus, are found only on rocks, stone walls, and buildings; they are swift. Some-and these are the most depressed in body-are rather sluggish, e. g. S. spinosrts, and spend most of their time on the ground between spiny growth of hedges and low trees, which they ascend a little way, in short rapid jerks, when alarmed. Lastly, /S', rnicrolepidotus is truly arboreal, ascending the trees in the morning, with the sun, right into the green tops, where they hunt for insects. This species has the greatest possible alti-tudinal range ; from the hot country of Southern Oaxaca, only a few hundred feet above the level of the sea, to the upper tree-line of Citlaltepetl, about 13,500 feet elevation. Many species are viviparous. According to my own observations, the following : acanthinus, ceneus, formosus, rnicrolepidotus, scalaris-all gravid in the months of July to September. Iguana rhinolophus is interesting for various reasons. It is the largest Lizard in Mexico, attaining a total length of about 5 feet. Always arboreal and aquatic and truly tropical, it occurs in the whole of Central America, but in Mexico, north of the Isthmus, only in the States of Vera Cruz and Southern Oaxaca, everywhere strictly below the Plateau, and on the Pacific side it has been recorded only from Manzanillo near Colima and near Mazatlan; undoubtedly also near San Bias and in the lower reaches of the Balsas, but this information I have only from hearsay. I never found it in Guerrero. The creature requires permanent, rather sluggish rivers, or deep pools in the savannahs. They climb about in the trees, eating the succulent leaves, which they bolt without much chewing, for instance those of the guava tree. Favourite places for resting are the branches which overhang the water, into which they plump with a loud splash, sinking at once and remaining at the bottom for many minutes. Whilst the adult are dusky, the young are grass-green and are frequently found in the tall grass at the edge of a pool. They at once take to the water and swim to the bottom, with their legs laid back and propelling themselves, like newts, by rapid undulating motions of the tail. The eggs are buried in the soft soil, among the roots of a tree, always near the water, in the month of May; by the end of July they are already hatched. They are known as Guanas or Iguanas. Ctenosaura acanthura is a common Lizard of the hot and warm |
