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Show 2 2 0 DR. H. GADOW ON MEXICAN [June 6, the Portuguese 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. ccinaliculatus.-Fifth finger very small, clawless; three pores on either side in front of the enlarged preanal scales; tail twice as long as the head. Nasal plates widely separated. Specimen in Berlin Museum...... Right hand 1 . 2 . 3 . 4 . 0 ; Left 1 . 2 . 3 . 4 . 0. British Museum I ........................ „ „ 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. „ „ I I ................................ „ „ 1 . 2 . 3 . 4 . 5 ; „ 1 . 2 . 3 . 4 . 5. „ I I I .............................. „ „ 1 . 2 . 3 . 4 . 5; „ 1 . 2 . 3 . 4 . 5. (Fifth finger on both hands well-developed in Balsas II. and III.) C. biporus (Euchirotes biporus Cope).-13 specimens in Smithsonian 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 front. C. 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. Rhineura of Florida has been found in the Oligocene of South Dakota, whereby the former range is extended considerably to the north. It is very difficult 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." Resume of the Distribution of Mexican Lacertilia. Gechonidce.-Chiefly Antilles, North-western South America and adjoining Central America. Eublepharidce.-North-western Mexico and Mexican Tierra Caliente. |