- 3 



The hypapophyses of the vertebrae along the esophagus jut into its 

 dorsal wall, adhering rather solidly to the vertical surface of the muscle 

 by means of a connecting tissue. However, the hypophyses in the Amurian 

 runner do not perforate the wall of the esophagus and do not enter its 

 cavity, as in the egg snake. Also, the lower surfaces of the hypapophyses 

 in this runner are approximately of identical form, whereas in the egg 

 snake the hypapophyses of the 22 - 26th vertebrae are sharply different 

 from all the others in their more or less spherical form. 



The observation of the swallowing and crushing of large eggs by the 

 Amurian runner combined with the structure of the fore section of its spinal 

 column leads me to the conclusion that the latter is an adaptation for 

 crushing egg shells in the esophagus. The mechanism of this adaptation 

 consists of the fact that having swallowed the egg the runner squeezes it 

 between the tips of the f oreward-directed hypapophyses, which are wedged 

 in the wall of the esophagus, and shortening the muscles, presses the 

 shell and breaks it. 



1 have observed a similar adaptation in the spinal column in a number 

 of other snake species which eat eggs of various birds along with other 

 types of food. Similar structure of the hypapophyses occur on the vertebrae 

 lying along the esophagus in the figured runner (E. d ione ) , 4-striped runner 

 (E. quatour lineata ) and insular runner (E. cl imacophora ) , and also in the 

 American E. obsoleta . Thus, in the figured runner the hypapophyses of the 

 5 - 6th anterior vertebrae are directed, as in the other species, backward 

 and downward, the two following stand almost vertically, then their direc- 

 tion changes and beginning with the 8 - 9th vertebrae, they are turned 

 forward and downward (fig. 3). The last vertebrae bearing hypapophyses are 

 the 34 - 35th (in 3 specimens). 



Gans and Oshima (1952), not knowing of my data on the adaptation of 

 snakes to eati.ig birds' eggs (Chernov 1945), in 1952 published an article 

 on the same subject. The species on which their observations were based 

 was the insular runner (E. cl imacophora ) . Their publication confirm my 

 datal and -- with the addition of E. guttata , E. taeniura and E. car inata -- 

 increase the number of species, in the structure of the spinal column of which 

 the authors were able to observe analogous characteristics. It is inter- 

 esting to add that, according to those authors, in E. car inata several 

 hypapophyses perforate the wall of the esophagus, which is not found in 

 other species of the genus Elaphe . It must be said that in my other 

 investigations of species of the genera Elaphe (E. ruf odorsata , E. 

 longissima , E. hohenackeri ) and Coluber all the hypapophyses are directed 

 backward and below (fig. 4). 



(( In their material the last hypapophysis bearing vertebra in the "spotted?" 

 ( ) runner is the 39th, which testifies to the possibility of some 



variations in the number of vertebra present in one and the same species.)) 



