62 ^- J- Anderson. A Discussion on the Significance of Muscular Anomalies. 



usual. This would explain also the altered condition of the sym- 

 physis. 



Every one is familiar with the records of Prof. Grüber, of these 

 some would seem to indicate reversion. The variations of the Extensor^ 

 Indicis may be cited here. The description is abbreviated, ready to 

 hand, in the International journal of Medical Science of a few Years ago. 



The Extensor Indicis et medii is present in 14 per cent in man. 

 Sometimes in the Chimpanzee and Orang. 



Extensor Indicis et pollicis united with an extensor indicis pro- 

 prius occurs in Felis domestica. But no Extensor proprius pollicis is 

 present. 



Extensor indicis et pollicis is present in Dasypus. 



Extensor indicis, medii et annularis, Hylobates generally. 



Extensor pollicis, indicis et medii, Hapale, Solenodon, Didelphis. 



Extensor indicis brevis (i. e. Indicis et medii) =: Extensor brevis 

 digitorum of many Edentates, Manis, Myrmecophaga. 



One could conceive it possible that imitation, conscious, or un- 

 conscious, would lead to some of these variations, or that an attempt 

 to perform some new action would ultimately lead to the formation 

 of new structures. 



The work of Sir John Struthers on the Supracondyloid Process 

 may be alluded to. It will be remembered that the hereditary character 

 of this process was established for man. Present in the Lemurs and 

 lower Apes, it is absent in the higher types. Cuvier noted that it 

 was present in the Cave Bear. It is often present in Felines, always 

 in Armadillo, never in the Sloth. The breadth of the Humerus has 

 something to do with its presence (Struthers, International Medical 

 Congress 1891). 



C. Darwin, as we know, was less concerned with the origin of 

 Anomalies than with the ultimate chance of their persistence as a 

 natural mark, of Type. His book on the Emotions shows how closely 

 he connected structural varieties, temporary and permanent, with the 

 central nervous system. 



