154 LIZARDS OF THE PHILIPPINE ISLANDS 



''Body protected by bony plates underlying the scales, which 

 are cycloid-hexagonal, rarely rhomboidal, imbricate, arranged 

 quincuncially. These plates provided with symmetrical tubules, 

 which usually consist of a transverse one anastomosing with 

 several longitudinal ones. Head covered with symmetrical 

 shields; an azygos occipital is rarely present. Pupil round. 

 Eyelids well developed. No femora;i pores." (Boulenger.) 



This is the largest family of the Sauria; it is cosmopolitan 

 in distribution. The various species are adapted to many 

 modes of life; some are arboreal, some terrestrial, some subter- 

 restrial, and some semiaquatic. Many are oviparous, but most 

 of them are ovo viviparous. These characteristics are of little 

 more than specific value. Certain members of a genus may 

 produce eggs which are incubated wholly outside the body, and 

 others bring forth living young. This is shown in two closely 

 related species of Mahuya; M. multicarinata lays eggs, whereas 

 M. multifasciata brings forth living young. The same condi- 

 tion obtains in two Philippine species of Leiolopisma ; L. pul- 

 chelliim is oviparous, and L. semperi gives birth to living young. 



Another character which ordinarily merits generic distinction 

 fails in this group. This is the degree of development of the 

 legs and digits. A very notable example is the Philippine genus 

 of Brachymeles. Here we find a complete retrogression from 

 the pentadactyl species with moderately developed limbs to 

 small burrowing species with no external vestiges of legs. Thus 

 we have pentadactyl and tetradactyl forms; species having 

 small legs and no digits, and finally one species with no legs. 

 The same retrogression is paralleled in the genus Lygosoma 

 Gray (non Boulenger). 



Many species of the Scincidae are very small. In certain 

 instances these small ones agree so closely with one another 

 in the scalation of the head and in markings that it is almost 

 impossible to define them so they may be recognized as different 

 species. This is especially true of certain small ones belonging 

 to the genus Sphenomorphus. A difficulty encountered in the 

 study of the Philippine skinks is that considerable variation 

 occurs in the same species in coloration and scalation, especially 

 in those found on various island groups. In some cases I have 

 resorted to trinomial nomenclature to record these apparently 

 constant variations. There are eleven genera in the Philippines. 



Key to the Philippine genera of the Scincidas. 



a\ Palatine bones in contact on the median line of the palate; tympanum 

 either superficial, deeply sunk, or covered. 



