746 MR. P. L. SCLATER ON ANIMALS IN THE MENAGERIE. [Dec. 5, 



pi. iv. fig. 2) most clearly figures a double beard in P. expansa. 

 Thirdly, Dumeril and Bibron (Erp. Gen. i. p. 584) give as a generic 

 character of Podocnemis "deux barbillons sous le menton," and again 

 speak of these {ibid. p. 385) in describing P. expansa. Fourthly, 

 Peltocephalus, according to the best authorities, has no chin-beard 

 at all. So that I do not think it can be truly said that the one- 

 hearded chin is a character of the family Peltocephalidoe. 



As regards the question whether P. unifilis in the stage described 

 by Prof. Troschel (with which the specimen now before me agrees 

 very exactly, except that the spots on the head are bright yellow, not 

 white, the colour in Prof. Troschel' s specimen having been proba- 

 bly destroyed in spirit) is a good species, I have not been able to 

 come to a very satisfactory conclusion. We require more informa- 

 tion concerning the history of the Amazonian Tortoises and their 

 various stages before we can come to positive results on the subject. 

 Dr. Peters some time ago informed me that he considered P. unifilis 

 a good species, and had several specimens in the Berlin Museum ; 

 and I see that he has recently recorded the occurrence of a Tortoise 

 on the Ucayali under this name*. 



Mr. Edward Bartlett informs me that he believes that he met 

 with four species of the genus Podocnemis during his Amazonian 

 travels, namely : — 



1 . The Tartaruga grande or Cherapa grande, which is " common 

 all over the Amazons, and grows to a length of 2 feet or more, 

 and lays from 100 to 150 soft round eggs, generally in steep sand- 

 banks." This is no doubt Podocnemis expansa (Schweigg.) ( — Emys 

 amazonica, Spix), Dum. et Bibr. ii. p. 585. There can be no 

 question, I think, that this species always has two barbules under 

 the chin. Spix, it is true, says of it "gula unicirrhosa ;" but 

 Wagler, who figures from Spix's specimen, as I have said above, 

 gives two. 



2. The Cherapilla, a smaller species, found on the Huallaga 

 and Ucayali. "It grows to a length of not more than 18 inches, 

 and lays from twenty to forty eggs in rather a deep hole on flat 

 sand-banks." The eggs, of which I exhibit Mr. Bartlett's spe- 

 cimens, are oval, and their shells quite hard; they measure 1-8 in. 

 by 1-35. 



This I suppose to be Podocnemis dumeriliana (Schweigg.) or 

 Emys macrocephala of Spix. Whether this species has one or two 

 barbules on the throat I cannot quite decide. A fine dried specimen 

 (measuring about 1G in. in length of the upper shell) which Mr. E. 

 Bartlett has lent to me has certainly only one central barbule. But 

 in the figure of the head of P. dumeriliana given by A. Dumeril 

 (Arch. d. Mus. vi. pi. xviii. fig. 3) two barbules are plainly shown. 



Dr. Gray has pointed out the differences in the form of the 

 ridges on the alveolar surface of the upper jaw which separate this 

 species from P. expansa, and which are well shown in the four 

 skulls now exhibited from Mr. E. Bartlett's collection. But Dr. 

 Gray has not remarked on another still more characteristic point 

 * Monatsb. Ac. Berl. Aug. 3, 1871. 



