Baur.] Jib [May 5, 



B. Sternum narrow at each end. The margin of the shiekl expanded, 

 flexible, thin. Sternal callosities four. 



2. Tyrse. Head moderate, ovate, narrow in front ; lips thin. Ribs 



eight pair, forming a disk with the vertebrae when young. 



3. Dogania. Head very large, dilated behind, narrow in front ; lips 



thin. Ribs eight pair, not united in a solid disk until late in 

 life. 



4. Chitra. Head dilated behind, broad and short in front ; lips very 



large, swollen. Ribs eight pair. 



5. Trionyx. Head moderate, ovate, narrow in front. Ribs seven 



pair." 



The following species are placed with the different genera : 



Einyda — E. punctata, E. seuegalensis. 



Tyrse — T. gangetica, T. javanica, T. perocellata, T. nilotica, T. rafeht. 



Dogania — D. subplana. 



Chitra — Ch. indica. 



Trionyx — T. ferox, T. muticus. 



Gray did not accept Fitzioger's classification, because, he says, the 

 characters given by him "alter with the age of the animals" (p. 50). 



It may be noted here that in 1843 Fitzinger* had separated the Aspido- 

 nectes javanicus Wagl. under the name of Potamochelys, without giving 

 any characters. 



In 1854, Peters f established the genus Cycloderma for Cydoderma frcn- 

 atum Peters. 



The last work we may mention, before discussing the question, is that 

 of Agassiz.:}: 



He retains the following genera : 



Trionyx Wagler {Emyda Gray). 



Chitra Gray. 



Dogania Gray. 



Cydoderma Peters. 



Aspidonectesy(?ig\. {2'r. javanicus, T. agyptiacus, T. spinifer, A. asper, 



A. nuchalis, A. emoryii). 

 Plaiypeltis Fitz. (type, Tr. ferox Schwe'xgger, 2V. gangeticus Cav.). 

 Amy da Ag. (type, T. mtUicus Les.). 



It is now the time to discuss the value of the different genera proposed. 

 There is no doubt about Trionyx Wagler, for this genus has to stand with 

 Testudo punctata Lacep. as the type ; Emyda Gray and Cryptopus D. et 

 B. are synonyms of it. 



* Fitzinger, L., Sj/stenia Reptilium Vindobana', 184S, p. 30. 



t Peters, W., " Ueber die auf seiner Reise nach Mosambique bcobaehtcten Schildkroten," 

 Jkrl. Acad. Monatsb., I!r51, pp. 215, 216. 



J Agassiz, Louis, Contributiops to the Natural History qf the United States, Vol. i, Boston, 

 1857, pp. 394-397. 



