CHAPTER XII 

 THE EYES OF AMPHIBIANS 



One of the most interesting figures associated with the study of the eyes 

 of Vertebrates was ANDRE-jEAN-FRANgois rochon-duvigneaud (1863-1952) 

 (Fig. 395). Born in the Dordogne, he studied medicine in the Faculte de Bordeaux 

 and in 1889 became an interne des Hopitaux de Paris at the Hotel Dieu and a 

 Chef de Clinic in 1895. A cUnician and operator of repute, he contributed a 

 number of excellent papers to ophthalmic literature, but he was always interested 

 in anatomy. His doctorate thesis (1892) was on the anatomy of the angle of 

 the anterior chamber and the canal of Schlemm — a historic paper. His anatomical 

 researches on the human eye led him to study the eyes of animals and from 1916 

 onwards numerous papers on this subject full of painstaking and careful observa- 

 tions of unusual originality and exactitude appeared from his pen. A study of 

 these papers reveals even to the casual reader the delight it must have given 

 him to produce them, and it is not surjarising that he retired from clinical jaractice 

 in 1926 and devoted all his time, working in a small laboratory at his home, to 

 the study of the eyes of x'arious species and spending much energy in observing 

 the habitsof animals in all the parts of France. His numerous papers on compara- 

 tive anatomy were collected together in his classical textbook, Les Yeux et la 

 Vision des Vertebres (1943), and earned him a well-deserved international 

 reputation. Nor was he withovit honour in his own country, having been elected 

 to the Academie de Medecine in France in 1940. At his death it was truly 

 written : " Homme droit, desinteresse, serviable, c'est un grand savant modeste 

 qui disparait." 



AMPHIBIA {ayi(f)[^iov, double life) mark the transition from aquatic to 

 terrestrial life. The early forms found in upper Devonian strata and 

 probably, as we have seen,^ sprung from the lobe-finned Crossoptery- 

 gians, are extinct. In Carboniferous times- these reached their prime 

 and some species attained a gigantic size ; today relatively few types 

 are extant and these, usually small in size and sluggish in habit, 

 generally live near the water's edge. The main features wherein they 

 differ from fishes are determined by their life on land — the disappear- 

 ance of the gills in adult life, the development of lungs (with a three- 

 chambered heart) from the air-bladder, the transformation of the 

 lobed fins into chgital limbs, the (usual) loss of the scaly exoskeleton, 

 the adaptation of the ear to aerial vibrations and of the eye to aerial 

 vision. 



The surviving members of this once populous class are divided into three 

 orders : 



1. APODA (d, without ; ttov?, ttoSos, afoot) (or Gymnophiona, yu^vo?, naked; 



ocfiLoveos, serpent-like), a peculiar archaic worm-like type without limbs and of 



burrowing habit, are found in the mud-banks of tropical countries. They are 



1 p. 235. 2 p 754 



333 



