OCR Text |
Show 1871.] MR. P. L. SCLATER ON ANIMALS IN THE MENAGERIE. 747 of difference in the skulls of the two species, to which Mr. Bartlett has called my attention. In P. dmmeriliana there is a large oval fossa (af, fig. 2), about two tenths of an inch in depth, immediately in front of the aperture (ac.) in which the columella is lodged. This fossa does not exist in the skull of P. expansa (fig. 1), or at least is only shown by a slight depression of the surface in the same spot. Moreover the large somewhat triangular-shaped fossa behind the aperture (pf), which occurs in both species, is very much larger in P. dumeriliana than in P. expansa. Fig.l. Fig. 2. Right tympanic rings of Podocnemis expansa (fig. 1) and P. dumeriliana (fig. 2). pf. Posterior fossa, af. Anterior fossa, ac. Aperture of the columella. 3. The Tortoise recently named by Dr. Gray Bartlettia pitipii*, which M r Bartlett met with only near Sarayacu, on the Ucayali. This, he states, " lays from nine to twelve eggs only, on the flat sandbanks, about fifty or sixty yards from the water." The eggs, of which I exhibit two specimens from Mr. Bartlett's collection, are oblongo-oval in shape and soft-shelled, measuring 1*7 by 0*9 inch. There is no question about this Tortoise being a Podocnemis, in m y opinion, and probably of a species different from P. expansa and P. dumeriliana. But I consider that it may be referable to Emys erythrocephala of Spix, with which it agrees iu nearly every particular. In the first place Spix's species is unquestionably a Podocnemis, but has been referred by some authors to P. dumeriliana and by others to P. expansa, both of which species Spix has figured under other names. Wagler, who had the advantage of the use of Spix's specimens, says (Nat. Syst. d. Amph. p. 135) "Emys erythrocephala, Spix, which belongs to this genus (i. e. Podocnemis) differs from Emys expansa only in the circular excavation at the end of the thorax by the tail. Perhaps this is only individual." The complete specimen of the so-called Bartlettia pitipii in the British Museum, as will be seen by the accompanying sketch (fig. 3, p. 748), presents this feature to a certain extent, although not to the extent given in Spix's figure. * P. Z. S. 1870, p. 720. |