138 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



1890 T. indefatigahiUs Baur Indefatigable Island 



1890 T. duncanensis Baur Duncan Island 



1890 T. abingdonensis Baur Abingdon Island 



1890 T. hoodensis Baur Hood Island 



1892 T. harnngtonensis Baur Barrington Island 



1892 T. jacobii Baur James Island 



1903 T. grayi magnns Heller Narborough Island 



T. hoodensis is merely a substitute name. T. lemniscatus is 

 a synonym of T. hivittatns, as T. abingdonensis is of T. pa- 

 cificus. Thus we have left eleven names, which have been 

 given to the lizards of as many different islands. How many 

 of these are entitled to recosj-nition ? 



Relations and List of Kinds Recognized 



There can be no doubt that Baur was right in his belief that 

 only one kind of Tropidurus occurs on any one island. It is 

 true also that many of the islands have distinct and peculiar 

 forms of Tropidurus. But when we come to study these liz- 

 ards we find that differentiation has proceeded much farther 

 upon some islands than upon others. The most distinct of all 

 are the Abingdon, Bindloe, Duncan, and Chatham lizards. 

 There can be no doubt that they should be regarded as four 

 species. The next in point of distinctness is the Hood Island 

 form. Then comes the Charles Island lizard, which in cer- 

 tain characters resembles that of Hood, while in others it is 

 more like that of Barrington. The last mentioned (Barring- 

 ton form) stands next as a sort of connecting link between 

 the lizards of Hood and Charles islands on the one hand, and 

 its still closer relatives of the central and western islands, as 

 yet unmentioned, on the other. The lizards of these three 

 islands (Hood, Charles and Barrington) certainly are distinct, 

 but there easily may be some difference of opinion as to 

 whether they should rank as full species or as subspecies. The 

 Tropiduri of Indefatigable, James, Jervis, Albemarle, and 

 Narborough islands are most closely related. Very large 

 series enable us to show that the lizards of these islands are not 

 absolutely identical, but differentiation is as yet so slight that 

 it seems best to use but one name for all. 



We, therefore, shall describe the Tropiduri of the Galapagos 

 Islands under the following names : 



