536 



Ohservations on a fey) Species of Geckos, 



[No. 5, 



instance, while studying the forms, and closely examining the habits 

 of the geckos now alive in my collection, that it is incumbent on me 

 simply to adopt the genus Gecko, for every species in the family 

 rather than place them in the several genera, enumerated in modern 

 classification. G-eckoid lizards bear a strong similarity to each other 

 and are in themselves unmistakable. One specimen alone is almost 

 sufficient to mark the entire type, notwithstanding that on comparing 

 species, one with another, a marked difference is visible, quite sufficient 

 to distinguish species, but insufficient in my opinion for a division of 

 the genus Gecho into genera, to meet alterations caused by size, or 

 slight differences of form. I have therefore adopted the genus Gecho 

 for all these lizards in my collection, whose habits I have lately 

 been enabled to observe closely. The word Gecho, is evidently taken 

 from the sound, uttered by very many of the species, in which c yecko ' 

 or i gecko,' or c chucko,' is distinctly audible. From the formation 

 of the pupils of their eyes, it will at once be remarked, that they 

 are more or less nocturnal in their habits. In many the pupil 

 strongly resembles that of a cat, when much contracted. In • the 

 day, it is contracted to a fine dark hair line, but this is only the 

 case with those which are most nocturnal ; others again which are 

 diurnal in their habits, preserve the fullness and rotundity of the 

 pupil in ordinary strong lights : this is the case with my Gecho 

 chameleon (Phelsuma Andamanense of Blyth,) a very beautiful species, 

 peculiar to the Andamans, where it is found in great abundance. The 

 pupil of, this species remains round in all lights, and is intensely black; 

 whereas, in my Gecho parches, which, I think, may prove to be Hemi- 

 dactylus coctcei auctorum, the irides, which are of a peculiar bronze and 

 very metallic hue, shew during the day simply a very fine vertical 

 hair-like pupil. Almost all the other small species have the same, 

 but in Gecho touchtay of mine, which is Platy dactylus verus, the irides, 

 which are of a yellowish green, instead of having by day-light a hair- 

 like contracted pupil, have five or six minute unconnected dots vertically 

 arranged, which, on the reduction of light, rapidly increase and connect 

 themselves, forming in the dark a full pupil. This latter I ascertained 

 from a gecko that had died in the dark, the pupil of which I found to 

 be fully developed and round. Geckos seem to (feed entirely on insects ;] 

 the localities which they frequent therefore, are those best suited to 

 the description of insects they feed on, for capturing which, nature 



