GECKONID^. O 



movable lids, and in Ptenopns the upper lid is sufficiently developed 

 to cover the eye nearly completely. 



The tympanum is more or less exposed, except in Teratolepis, 

 in which genus it appears to be completely concealed under the 

 scales. The tongue is fleshy, moderately elongate, very feebly in- 

 cised anteriorly, and capable of protrusion out of the mouth. 



The teguments are nearly always soft, and consist generally of 

 granules or tubercles on the dorsal surface, of small imbricated 

 cycloid or hexagonal scales on the ventral surface. Some Geckos 

 are entirely covered with scales of the latter description, which 

 attain their highest development in Teratoscincus, Teratolepis, and 

 GecJcolepis. 



The habits of the Geckos are highly interesting and deserve special 

 attention, as but few observations have been made on them. Some 

 inhabit arid regions, sometimes burrowing in the sand ; others are 

 arboreal, living on shrubs or in woods, concealing themselves under 

 stones or under the bark of trees during the daytime ; others live on 

 rocks ; others have become the commensals of man, and they again 

 may be divided into two groups — those living inside, those living out- 

 side houses. Most are nocturnal, but some are diurnal. CoL Tytler, 

 in a very interesting paper on the habits of Geckos *, observes that 

 " although several species of Geckos may inhabit the same locality, 

 yet, as a general rule, they keep separate and aloof from each 

 other ; for instance, in a house the dark cellars may be the resort 

 of one species, the roof of another, and crevices in the walls may 

 be exclusively occupied by a third species. However, at night they 

 issue forth in quest of insects, and may be found mixed up together 

 in the same spot ; but on the slightest disturbance, or when they 

 have done feeding, they return hurriedly to their particular hiding- 

 places." 



Many Geckos utter sounds, probably produced chiefly by a move- 

 ment of the tongue against the palate, and in which yecico, chucko, 

 tocTcee, or something similar, is distinctly audible. A. Smith says that 

 a South- African Sand-Gecko {Ptenopus garrulus) utters during the 

 day a sharp sound somewhat like chicle, chich ; and he adds that the 

 number thus occupied is at times so great, and the noise so dis- 

 agreeable, as to cause the traveller to change his quarters. 



The eggs are round and with a hard shell. Ovoviviparism has not 

 been observed in this family. Males are generally distinguished 

 from females by a larger size, the swelling of the base of the tail, 

 and the presence of femoral or prseanal pores, which are constantly 

 absent in the latter. 



The GecJconidce are represented in the hotter parts of all the 

 regions of the world. They are most numerous in the Indian and 

 Australian regions. 



* Journ. As. Soc. Beng. xxxiii. 1864, pp. 535-548. 



