294 THE ZOOLOGIST. 



precursors, the huge Ichthyosauri. In the latter, however, and in 

 these only of all air-breathing back-boned animals, there are 

 indications that the number of the digits exceeded five. 



As to the lowest air-breathers referred to — the Frogs, Toads, 

 and Efts— I will but refer to the foot of the Frog, in which we 

 meet with a condition reminding us in a distant way of 

 those very different animals, the Lemurs. In the Frog two 

 of the tarsal bones are elongated, so as to merit the name 

 of "long bones," and to form a separate segment of the hind 

 limbs. 



To return to the question of the resemblance between " the 

 hands" and "the feet" in the same individual. There are 

 certain very curious facts which point to some deep and hidden 

 cause of this resemblance of a more profound nature than any 

 similarity of use and employment. Thus, birds present us with 

 examples of the greatest divergence between " hands " and 

 " feet," and yet, at the same time, they sometimes singularly 

 illustrate the hidden affinity between these two parts. Thus 

 certain breeds of fowls and pigeons develop what are technically 

 called " boots " on the feet ; that is to say, their feet put forth long 

 feathers resembling those of the wing, and they grow from the 

 very parts of the foot which correspond, serially, with the long- 

 feather bearing parts of the hand. 



There are many curious cases of diseased conditions in man 

 which illustrate and display this hidden affinity. Thus Sir 

 James Paget has recorded cases in which psoriasis has similarly 

 affected the palms of the hands and the soles of the feet in one 

 individual, and the backs of the hands and the backs of the feet 

 simultaneously in another individual. Analogous observ^ations 

 have been made by Dr. William Budd and others. 



Again, those curious cases of congenital malformations called 

 "monstrosities" also seem to illustrate this curious tendency to 

 develop serial similarity. Professor Burt Wilder, of the United 

 States, has noted many instances in which similar deformities 

 have co-existed in the little fingers and in the little toes, or in the 

 thumbs and the great toes ; and M. Isidore Geoffroy St. Hilaire 

 has recorded various cases in which similar defects of develop- 

 ment have co-existed in the hands and feet of the same in- 

 dividual. 



Such phenomena point to some very recondite and deeply 



