368 THE AMERICAN NATURALIST [Vol. XLII 



while all other forms would be excluded from this class 

 and would have to be placed among the Reptilia, where 

 they probably belong ; whether they are to be considered 

 as a subclass of the Reptilia or not, does not concern us 

 here. 



In the forelimb there are never more than four digits 

 either in the Paleozoic Branchiosauria nor in the later 

 Caudata. So far as I am aware, there is no paleonto- 

 logical evidence to show that there ever were more than 

 four digits in the hand of the caudate Amphibia and in 

 this discussion the first digit will be considered as Xo. I., 

 the second digit as No. II. and so on. Fritsch, it is true, 

 has figured five digits in the hand of Branchiosaurus sala- 

 mandroides Fr. (Fig. 7), from the Permian of Bohemia, 

 (4) but in giving us a glimpse into the material on which 

 his restoration is based there are only four digits pre- 

 served in the hand, although Fritsch says the first had 

 been lost. I doubt if there ever were more than four, and 

 the digits in Fritsch 's specimen were all preserved. In 

 all of the Permian forms from Saxony Credner has 

 figured four digits in the hand (Figs. 5-6). 



The specimens recently described by Thevenin from 

 the Upper Carboniferous of France (5) show only four 



