Dr. G. Baur on Meiolania. 39 



Chelodma {Chelys not at hand). Besides, this would have 

 nothing- to do with the condition found in the Ciyptodira, 

 To expLain this 1 give a description of the reLations between 

 pra^frontals, palatines, and vomer in the Testudinata. 



In all the Cryptodira the prefrontals show two inferior 

 processes : one which we call the inner process is connected 

 with the vomer and the inner portion of the palatines 5 the 

 other, the outer process, is connected with tlie maxillary, or 

 may even reach the outer portion of the palatines. Between 

 these two processes and the palatines and maxillaries we find 

 the foramen nasopalatinura, 



a. CryiJtodira. 



Chelydridas, Dermatemydida3, Staurotypide, Cinoster- 

 nida3. 



Inner process of prajfrontal in extensive connexion with 

 vomer and palatines ; outer process in no connexion with 

 palatines. 



The Cheloniidai show the same condition, but in some 

 forms the connexion between the inner process and the pala- 

 tines has gone. We may distinguish the following stages: — 



Euclastes. — Like Chelydridas. 



Chelonia. — Inner processes clearly connected with palatines. 



Thalassochelys. — The ends of the inner processes touch the 

 palatines. 



Colpochelys, Caretta. — No connexion between inner pro- 

 cesses and palatines 



Dermochelydidce. — Connexion still more reduced ; ends of 

 inner processes touching vomer only. 



Emydidce and Testudinidce. — A similar condition to that in 

 Chelydrid^e we find in some of the Emydidas {Trachemys 

 serrata^ Ptychemys concinna and mohlUensis). In others the 

 outer prasfrontal process begins to touch the palatines {Mala- 

 coclemmys, Chrysemys^ Terrapene^ Clemmys). Or in many of 

 the Testudinidai a strong connexion exists between this pro- 

 cess and the palatines ; hence the foramen nasopalatinum is 

 formed by the pra2frontals and palatines only. This foramen 

 may be very much reduced and nearly disappear [Emys 

 mekagris^ Clemmys guttata^ different Testudinidas, T. poly- 

 2yhemus). 



/S. CMlotce, Wiegm.* 

 The foramen nasopalatinum generally formed by pr^- 



* I use the name Cliilota^ in preference to Gray's name Triouyclioidea, 

 expressing only a superfamily. 



