56 R- J- Anderson, 



bringing about the result. The brain of a microcephalic idiot has 

 been examined with convolutions such as one would expect to find 

 in some early stem form of man: Macalister protests against every 

 muscular anomaly being regarded as an Atavistic Variation. Stability 

 is the rule in organs with a long ancestral History; instability in 

 those with a short History. The erect attitude is responsible for 

 many of the variations that are observed in man. Where a structure 

 recurs in man i:hat has already appeared in the lower animals, the 

 explanation may be that the two groups, after separation, may have 

 followed parallel lines. 



A prospective variation is termed an epigonism. Structures do not 

 advance always upwards they may retrograde. Note the eyes of cave 

 animals. The Pelvis is attached sometimes to the last lumbar vertebra, 

 and sometimes farther back than normal. The pelvis is moving farther 

 forwards according to Eosenberg, farther back according to Patterson. 

 It is suggested that a Gibbon-like Ancestor (as in the Prothylobates 

 of Dubois) had 26 presacral vertebrae. There are now in the Gibbon 25, 

 in the Orang 23, in Man, Gorilla and Chimpanzee 24. The Orang has 

 reached its goal, backward variations are more common here than 

 forward ones. 



Abbreviations of the presacral region are more common in the 

 Chimpanzee and Gorilla than elongations. The arrangement of the 

 nerves does not change with the length of the presacral region. 

 Nerves do not change easily. But caudad shifting is more common 

 than cephalad shifting. The nerve supply of the Platysma in man 

 and the supply to the aborted Interossei in the horse are examples 

 of the slowness with which nerve structures change. 



Professor Shephej^d of Montreal mentioned the Musculus stern alis 

 as a new muscle in IVoman. His observations led him to think that 

 the Presacral region was being shortened. A dorso-lumbar vertebra 

 is more common in the Laplander. A pollex is sometimes found in 

 pigs, so is a perfect os trapezium. Shepherd's division of Anomalies 

 is into those with significance and those without significance. 



Examples of those with significance. 1 . Reversion to former types 

 or Atavism. The M. Chondro -scapularis; M. occipito - scapularis &c. 



