GENETIC TYPE AXD THE ENDOCRIXES 119 



of either the bassethound or bulldog stock. This then, on a 

 size basis for the breeds concerned, is a giant leg from a 

 large St. Bernard-like animal. It might be mentioned in 

 passing that this dog had a large, meaty thymus gland. 



The second skeleton, from 1488 9 , is of a long, straight leg 

 very similar in size and type to that of a foxhound. This is 

 the recessive long, normal leg with the ancestral hound bone 

 type. 



The third specimen, from 1311 & , is the long legged skeleton 

 of a bulldog typed animal weighing about 20 kilograms. His 

 head was bulldog-like and, in contrast to his giant brother 

 1312 $ , he had very scant thymus tissue. The leg skeleton is 

 closely similar to that of the bulldog shown as the third 

 skeleton in figure 1, plate 23. The scapula, humerus and 

 forearm bones are quite the same as those of the bulldog, 

 and the end of the ulna does not extend far below the distal 

 articular surface of the radius, this causing the foot to be 

 somewhat rotated laterally into the typical bulldog posture. 

 We find, therefore, among the long legged dogs in the F-, 

 generation of this cross, the long hound leg and the bulldog 

 leg derived from the parent stocks, as well as mixtures of 

 these two; in addition giant types with long legs arise, and, 

 in an opposite direction, dwarf and almost midget-like animals, 

 none of which has so far failed to show achondroplasia of 

 the legs. There may be, in this cross, some linkage between 

 achondroplasia legs and dwarf body size. 



The fourth leg skeleton is from 1313 S , a short legged 

 brother of the first and third specimens. This animal had a 

 bassethound-like body and a slight amount of thymus tissue, 

 merely mentioned here in connection with the large thymus 

 of the giant brother. The leg of this animal is interpreted 

 as mixed, si, for achondroplasia. It compares very closely to 

 the Fj leg skeleton shown at the right of the plate. The bone 

 type of this mixed si F 2 is more bulldog-like than that of the 

 Fj although, as we have pointed out before, bulldog type is 

 largely dominant over hound bone and the F! does show 



