Kansas llNiyEiisiTY Science Bulletin. 



Vol. IV, No. 15. SEPTEMRER, 1908. j^o'L°x^iv^ZT,' 



Vol XIV, No. 15. 



THE RELATIONSHIP OF THE TURTLES AND 



PLESIOSAURS. 



BY ROY L. MOODIE. 



(Contribution from the Zoological Laboratory, No. 182.) 

 Two text figures. 



THE question of the relationship of the turtles and plesi- 

 osaurs has interested zoologists since the time of Buck- 

 land, when the nature of the latter animals was first 

 clearly understood. At about this time, too, the first compari- 

 sons were made between them. Conybeare compared the 

 plesiosaur to a "turtle stripped of its shell." Mantell re- 

 marked that the structure of the plesiosaurs was such as to 

 "justify the graphic simile of an eloquent professor, that the 

 plesiosaurus might be compared to a serpent threaded through 

 the shell of a turtle."^ Again, Mantell tells us that the "ple- 

 siosaurus" combines the characters of several orders of rep- 

 tiles and has "paddles like the turtle." Ever since the utter- 

 ance of these statements an affinity between the two groups 

 has been claimed, and this has been based on various grounds. 

 It is the purpose of this essay to review the bases for the re- 

 lationship and to discover, if possible, the exact conditions in 

 regard to the so-called affinity. 



Parker stated that on account of the greater number of seg- 

 ments in the neck and tail of certain turtle embryos that there 

 was a suggestion of relationship between the turtles and ple- 

 siosaurs. He strengthened this suggestion by the statement 

 that some of the Cretaceous Chelonia possessed teeth. Seeley 

 called attention to the similarity in the method of ossification 

 of the limb bones in turtles and plesiosaurs, and referred to 



1. Mantell, 1851, Petrifactions, London, p. 341. 



(319) 



