PHYSICAL CHARACTERS IX MAN 35 



Ateliosis or true dwarfism is considered to be rather 

 rare. It is probably due to a defect of the pituitary. 



There is a fair number of cases recorded in which 

 offspring have been born to parents one or both of 

 whom were ateliotic. These, however, with the 

 exception of the cases quoted, have grown to a normal 

 size, if the}^ survived to adult years." Usualh' the 

 condition is found in only one generation. In an 

 exceptional case, an achondroplasic mother produced 

 an ateliotic son by an ateliotic father. In another 

 case, ateliosis occurred in father and son, and probably 

 in the grandfather. 



A condition in plants, which appears to correspond 

 with achondroplas}^, has been described in cotton, 

 under the name brachysm (Cook, 191 5). It consists 

 in a great shortening of the internodes without any 

 corresponding reduction in the diameter or in the 

 size or number of other organs. This condition exists 

 in the " bush " varieties of various vegetables and 

 cereals such as beans and peas, tomatoes, oats and 

 w^heat. Kempton (1921) has studied it in maize, 

 and finds that it is inherited as a simple recessive in 

 crosses with the normal tall. 



Ateliosis* in man appears to correspond to many 

 of the ordinary dwarf varieties of plants and animals, 

 though Davenport thinks it is due to dominant in- 

 hibiting factors. In some plants at least smaller cell 

 size is involved. A w^ell-known pedigree of the ate- 

 liotic type of dwarfism occurs in two families in the 

 Tyrol which have intermarried, and Pearson suggests 

 that it may here be inherited as a recessive from an 

 ancestral stock. 



Dwarfing of the t^'pe which produces general 

 reduction in size is often the result of unfavourable 



* Among horses, most ponies, such as the Shetland variety, 

 appear to be atehotic miniatures, while the Chinese pony, with 

 short legs and stout body, is apparently an achondroplasic dwarf. 



