CHAP. XIX.] EEPTILES. 40?> 



General Bemarks on the Distribution of the Lacertilia. 



The distribution of the Lacertilia is, in many particulars, 

 strikingly opposed to that of the Ophidia. The Oriental, 

 instead of beiug the richest is one of the poorest regions, both 

 in the number of families and in the numlier of peculiar genera 

 it contains ; while in both these respects the Neotropical is by 

 far the richest. The distribution of the families is as follows : — 



The Nearctic region has 7 families, none of which are peculiar 

 to it; but it has 3 peculiar genera — Chirotes, Ophisauriis, and 

 Phrynosoma. 



The Pala?arctic region has 12 families, with two (Ophio- 

 morida3 and Trogonophidse, each consisting of a single species) 

 peculiar ; while it has 6 peculiar or very characteristic genera, 

 Trogonoj^his in North Africa, Psammodromus in South Europe, 

 Hyalosaurus in North Africa, Scincus in North Africa and Arabia, 

 Ophiomorus in East Europe and North Africa, and Phrynocephalus 

 in Siberia, Tartary, and Afghanistan. We have here a striking 

 amount of diversity between the Nearctic and Palosarctic 

 regions with hardly a single point of resemblance. 



The Ethiopian region has 13 families, only one of which (the 

 Chamsesauridce, consisting of a single species) is altogether pecu- 

 liar; but it possesses 21 peculiar or characteristic genera, 9 

 belonging to the Zonuridae, 2 to the Sepidaj, 7 to the Geckotidse, 

 and 3 to the Agamidse. 



The Oriental region has only 8 families, none of which are 

 peculiar ; but there are 28 peculiar genera, 6 belonging to the 

 Scincidpe, 1 to the Acontiadse, 5 to the Geckotidae, and 16 to the 

 Agamidie. Many lizards being sand and desert-haunters, it is not 

 surprising that a number of forms are common to the border- 

 lands of the Oriental and Ethiopian regions ; yet the Sepida?, so 

 abundant in all Africa, do not range to the peninsula of India ; and 

 the equally Ethiopian Zouuridse have only one Oriental species, 

 found, not in the peninsula but in the Ivhasya Hills. The Acon- 

 tiadse alone offer some analogy to the distribution of the Lemurs, 

 being found in Africa, Madagascar, Ceylon, and the Moluccas. 



The Australian region has 11 families, 3 of which are pecu- 



D D 2 



