220 DR. H. GADOW ON MEXICAN [June 6, 



the Portug'uese Blanus cinereus they soon became flabby from 

 evaporation, but they soon swelled up again when the sand was 

 moistened. 



To split these creatures into three genera is ridiculous. But it 

 is very interesting that the specimens from the only three localities 

 known differ in the number of femoral pores, the length of the 

 tail, and in the reduction of the number of the fingers and claws. 



C. canaliculatus . — Fifth finger very small, clawless ; three pores 

 on either side in front of tlie enlarged preanal scales; tail twice 

 as long as the head. Nasal plates widely separated. 



Specimen in Berlin Museum Ri^lit hand 1.2.3.4.0; Left 1.2.3.4.0. 



British Museum 1 1, „ 1.2.3.4.0; „ 1.2.3.4.0. 



II „ „ 1.2.3.4.0; „ 1.2.3.4.0, 



Rio Balsas I „ „ 1.2.3.4.0; „ 1.2.3.4.5. 



„ II „ „ 1.2.3.4.5; „ 1.2.3.4.5. 



„ III „ „ 1.2.3.4.5; „ 1.2.3.4.5. 



(Fifth finger on both hands well-developed in Balsas II. and III.) 



C. hiporus {Euchirotes hiporus Cope). — 13 specimens in Smith- 

 sonian Institute, from La Paz in Lower California ; said also to 

 be common at Cape Lucas. 



According to Cope, with tail twice as long as the head, five 

 digits all clawed, with only one pore on either side, nasal plates 

 nearly in contact in fi'ont. 



fj. tridactylus {Hemichirotes tridactylus Duges). One specimen 

 from Tecpan, near Acapulco. Tail slightly longer than the head ; 

 only three digits, all with claws ; a pair of pores on either side ; 

 nasal plates widely separated. 



It is remarkable that Chirotes, the least reduced member of the 

 family, is the only Mexican representative of this presumably 

 ancient group, Khineura of Florida has been found in the 

 Oligocene of South Dakota,, whereby the former range is extended 

 considerably to the north. It is very diflicult to imagine how 

 Chirotes^ a helpless digger, without any chance of travelling, bound 

 to sandy soil, has managed to survive, unless we assume that it is 

 really a coast-form. Living in dunes, as it does at Cape Lucas, 

 Lower California, it may have ascended the Basin of the Balsas, 

 which river, from its mouth far into Guerrero, is bordered by 

 many sand-covered ledges. 



The arenicolous Chirotes has retained its fore-limbs, which, 

 although short, are rather well-developed, while those genera 

 which live in humus and rich soil have lost the limbs as usual. 



The natives had no proper name for these little creatures, but 

 described them as " culebritas con manitas." 



Resuine of the Distribution of Mexican Lacertilia. 



Geckonidce. — Chiefly Antilles, North-westei-n South America 



and adjoining Central America. 

 Eiihlepharidce. — ISTorth-western Mexico and Mexican Tierra 



Caliente. 



