Chap. I. SERIAL CONNECTION AMONG ANIMALS. 43 



of North America. Among Acalephs, the Berenice of New Holland. Among Polypi, 

 the true Fnngi(la> in the Indian and Pacific Oceans, the Renilla in tlie Atlantic, etc. 

 Many more examples might l)e quoted, were our knowledge of the geographical 

 distril)ution of the lower annuals more precise. But these will suffice to shoAv that 

 whether high or low, aquatic or terrestrial, there are types of animals remarkable for 

 their peculiar structure which are circimiscribed within definite limits, and this locali- 

 zation of special structures is a striking confirmation of the view expressed already 

 in another connection, that the organization of animals, whatever it is, may be 

 adapted to various and identical conditions of existence, and can in no way be con- 

 sidered as originating from these conditions. 



SECTION XII. 



SERIAL CONNECTION IN THE STRUCTURE OF AMIM.VXS WIDELY SCATTERED UPON THE 



SURFACE OF OUR GLOBE. 



Ever since I have become acquainted with the reptiles inhabiting different parts 

 of the world, I have been struck with a remarkable fact, not yt^i noticed by natu- 

 ralists, as far as I know, and of which no other class exhibits such strUving examples. 

 This fact is that among Saurians, as well as among Betrachians, there are famihes, the 

 representatives of which, though scattered all over the globe, fonn the most natural 

 connected series, in which every luik represents one particular degree of development. 

 The Scincoids,^ among Saurians, are one of these families. It contains about one 

 hundred species, referred by Dumeril and Bibron to thirty-one genera, which, in the 

 development of their organs of locomotion, exhibit most remarkable combinations, 

 illustrated in a diagram, on the followmg page. 



Fully to appreciate the meaning of tliis diagram, it ought to be remembered, 

 that the animals Ijclonging to this family are considered here in two different points 

 of view. In the first place, their zoijlogical relations to one another are expressed 

 by the various combinations of the structure of their legs ; some having four legs, 

 and these are the most numerous, others only two legs, which are always the hind 

 legs, and others still no legs at all. Again these legs may have only one toe, or 

 two, three, four, or five toes, and the number of toes may xnvy Ix'tween the fore 

 and hind legs. The classification adopted here is based upon these characters. In 



' Fur till' cliaracicrs of the family, see DuMKUii- See also CocTEAU, Etudes sur les Scincoides, Paris, 

 et Bir.iioN, Eii>oIologie guncnilf, vol. 5, j). 511. 1836, 4to. fig. 



