1893.] -J^^J ir.aur. 



Fitzinger divides, ia 1836,* the genus Trionyx into five sections : 

 Section 1. Trionyx, s. str. 



" 3. Aspidonectes. 



" 3. Platypeltis. 



" 4. FelocUscus. 



" 5. Amyda. 



The characters of Trionyx, s. str., are : "Ossicula marginalia distincta. 

 Os cervicale vertebralibus conjunctuni, in tola superficic rugosum. Ossa 

 costalia postica contigua." This section contains T. granosus Schweigg. 

 {T. punctata Lac.)- 



The characters of Aspidonectes are : " Ossicula marginalia nulla. Os 

 cervicale vertebralibus conjunctum, in tota superficic rugosum. Ossa 

 costalia postica contigua." (" Vertebralia septem ; costalia utringue 

 octo.") This section contains T. javanicus Geoffr., T. cegyptiacus Geofl'r., 

 T. Jiurum Gray, T. indicus Gray. 



The characters of Platypeltis are: "Ossicula marginalia nulla. Os 

 cervicale vertebralibus conjunctum, in medio tantum rugosum. Ossa 

 costalia postica contigua." ("Vertebralia sex, costalia utringue sep- 

 tem.") This section contains T. brogniarti Schweigg., T. ferox Schweigg. 



The characters of Pdodiscus are : " Ossicula marginalia nulla. Os cer- 

 vicale a vertebralibus separatum, in medio tantum rugosum. Ossa cos- 

 talia postica contigua." This section contains T. sinensis Wigm., 7'. la- 

 bi'itas Bell. 



The chuvsLCters of Amyda are: "Ossicula marginalia nulla. Os cervi- 

 cale a vertebralibus separatum, in medio tantum rugosum. Ossa costalia 

 postica interposito vertebralibus discreta." This section contains T. sub- 

 planus Geoffr., T. muticus Lesueur, T. euphraticus Geoffr. 



Bonaparte J follows mainly Fitzinger, but uses the generic names 

 Amyda Schweigg. and Trionyx Wagler. 

 "Amyda Schweigg. 



f Ossa costalia postica contigua. 



1. Aspidonectes Fitz. 



2. Platypeltis Fitz. 



3. Pelodiscus Filz. 



ff Ossa costalia postica interposito vertebralibus discreta. 



4. Amyda, Fitz. 

 Trlonyx Wagler." 



In 1844, Gray § gave the following synopsis of the genera : 

 "A. Sternum broad, wiih valves over the feet. The margin of the shield 

 supported by bones. 

 1. Emyda. Head moderate, sternal callosities five 



* Fitzinger, Leopold, " Eutwurf einer sj-stematischen Anordnung der Scliildkriiten," 

 Ann. Wien. Mas , i, 1836, pp. 119, 120, 127. 



Bonaparte, C. L., Chdoniorum Tabula Analytica, RcQiffi, 1836. 

 § Catalogue of the Tortoises, Crocodiles and Amphisbxnians, London, 1814, p. 46. 



PROC. AMER. PHILOS. SOC. XXXI. 141. 2 B. PRINTED JUNE 29, 1893. 



