276 ZOOLOGY. 



proAdded 'witli large labial and submaxillary scales. The teeth are variously 

 shaped and arranged, generally, however, inserted on the internal margin of a 

 common maxillary groove. Sometimes they are found in the palate. The 

 tongue is free, fleshy, flat, more or less extensible, the base sometimes con- 

 tained in a sheath, the apex always emarginate, sometimes deeply cleft. The 

 tail is very long and conical, the scales arranged in regular rings or Avhorls. 

 The skin is scaly, without projecting crests ; the dorsal scales variable ; the 

 central plates always larger, rectangular or rounded. Most of the species 

 exhibit femoral pores. 



The Lacertidce, like several other families of iSauria, are extensively dis- 

 tributed. About one third of the entire number of species belongs to America ; 

 only one, however, is found to North America. Somewhat the largest propor- 

 tion occurs in Africa ; Europe comes next in point of numbers. About 70 

 species in all are known to naturalists. Some occur in a fossil state, but, for 

 the sake of greater convenience, we shall refer to all of the lacertoid species 

 when we come to consider the VaranidcB. 



The Lacertidm may be conveniently divided into two sub-families, the 

 Pleodontes and the Ccelodontes. In the Pleodontes, the teeth are entirely 

 solid, without any internal cavity ; and attached by the bases and external 

 faces to the inside of the maxillary bones. They are usually bent a little out- 

 wards, especially those more anterior. All the species of pleodont lizards 

 belong to the New World. There are two strongly marked divisions of the 

 sub-family ; the one with the tail compressed, the other with it conical. 

 Those with compressed tails exhibit a striking resemblance to the crocodiles, 

 ■which is not diminished by their great size. The tail, flattened like an oar, 

 and with the surface increased still more by caudal crests, enables these ani- 

 mals to move with great readiness in the water, wdiich they inhabit to as great 

 an extent as the crocodiles. Their feet, like those of these latter animals, are 

 palmated. The Tupinambis of some writers is the Crocodilurus lacertimis, a 

 gigantic species nearly six feet in length, inhabiting the waters of Brazil and 

 Guiana. Thorktes dracana, found in Guiana, is still larger, individuals of 

 almost seven feet in length being known. Here the tail alone occupied nearly 

 five feet. 



The section of Pleodonts, embracing species wdtli conical tails, is more ex- 

 tensive than the last. Here the animals are more terrestrial or arboreal. A 

 single genus, Aporomera, is entirely destitute of femoral pores. Acra?itus, a 

 large South American genus, has but four toes visible on the hinder feet. 

 The other forms represent no remarkable deviation from the usual structure. 

 The genus Salvator {pi. 14:, Jig. 80) includes the true Tapinainhis or Sanve- 

 gardes. Individuals of eight feet in length are not uncommon. The genus 

 Cnemidophorus is interesting as containing the only representative of the 

 Lacertidae in North America. This species (C sex-lhieatus) occurs abun- 

 dantly in the Southern States, and as far north as north-eastern Maryland. 

 It is readily distinguishable from the other lizards by the six yellow lines 

 along the back, and the long tail. When pursued, it runs with incredible 

 swiftness, climbing trees with great facility, but not leaping from branch to 

 branch, like the green lizard, Anolis carol'mensis. 

 480 



