CHELONIA, 



789 



from Singapore, and it may be it is identical with species of Trionyx from Burma 

 wMch Theobald has described as having a smooth carapace. The figure shows the 

 remains of what appears to have been a dark reticulation of the upper surface of 

 the head. 



The plastron of T. stellatus is represented as having its hyoplastron and 

 hypoplastron and xiphiplastron covered with granulations as in Trionyx generally, 

 and with a light entoplastron. The specimens here figured (Plates Ixx to Ixxiii) 

 under the name of Trionyx pegnensis, have heads exactly agreeing with Theobald's 

 figure, Plate ii, l. c, referred by him to T. careniferus, Gray (?) = T. phayrei, 

 Theob. The eight specimens from Moulmein and the Irawady are all alike in 

 these particiilars, viz., that their heads have one coloration and one form so closely 

 corresponding in all their details to Theobald's figure that they must in this respect 

 be regarded as specifically identical with the head figured on Plate ii and Plate iii, 

 I. c. The heads of these animals exactly agree with the head in the British 

 Museimi named by Gray T. peguensis. There is, however, this remarkable difference 

 between their plastra and the plastron figured under the name of T. phayrei, that 

 animals of the same size as that figm-ed by Theobald have their plastra covered 

 with granulations as in the plastron of T. stellatus, figured by Theobald on Plate i 

 and Plate ui (I. c.) 



I have never seen a Trionyx from the Irawady with a head like that of T. stel- 

 latus, Geoff., apud Theobald. 



The skull of the adult figured on Plate Ixxii and Ixxiii of this work, and which 

 I here reproduce, natural size, Kgs. 29, 30 and 31, agrees with the skull oi the head 

 of the type of T. peguensis. The skull has a rather long symphysis marked by a, 



Fi2. 29. 



Skull of Trionyx peguensis, Gray. 



longitudinal ridge, and in the former character it resembles the skull of T. humm, 

 which, however, has no ridge, but rather a mesial groove. 



