246 CLASS XV. 



By modern writers, especially by Wagler and Tschudi, a great number of 

 genera have been adopted whioli replace the genus Rana of Linnaeus. The 

 greater part however of these divisions can only be noticed as sub-genera. 

 That these animals moreover represent the chelonians amongst the diplo- 

 pnoa is obvious, especially from the habitus of certain toads ; and it is 

 remarkable that in some of them a dorsal shield, however rudimentary, 

 may be observed. 



A. Tongue none. 



Pipa Laur., Merr., Dum. and Bibr., Asterodactf/Ius Wagl. 

 Body broad, depressed. Head broad, anteriorly acuminate, trigonal. 

 Eyes very small in the margin of jaw. Teeth none. Anterior toes 

 slender, with the last joint quadrifid. 



Sp. Pi2xi americana Laur., Rana Pipa L., Seba Thesaur. i. Tab. 77, Daud. 

 Ram., Gren. et Crap. PI. 31, 32, fig. 2, Blumenb. Ahbildung. naiurhistor. 

 Gegenst. No. 36 ; in Surinam and Brasil. The development of the young 

 takes place on the back of the mother ; the male places there the impreg- 

 nated eggs ; there are small cavities, or nearly hexangular cells, in which 

 the eggs are received. Here the young pipas undergo their change, and 

 do not quit the cells before they have lost their tail. See Fermin's 

 Ahhandlungen von den Surinamischen Krote oder Pipa, iihersetzt von J. A. 

 GcEZE. Mit 4 Kupfert. Braunschweig, 1776; F. G. Breyer, Ohsefvationes 

 anatomicce circa fabricam Ranee Pipce. Cum Tab. 2 sen. Berolini, 181 1; 

 C. Mayer, Beitrdge zu einer anatomisdien Monogra2^hie der Rana Pipa, 

 Nor. Act. Acad. Ccesar. Leop. Car. Vol. xii. p. 2. Only one species of 

 this genus is known hitherto. 



Xeiiopus Wagl., Dactylethra Cuv., DuM. and BiBK, Teeth in 

 upper jaw. Anterior legs small, slender, with toes subulate, thin, 

 subequal; posterior large, with soles palmate, three inner toes un- 

 guiculate. Head short, with eyes moderate. 



Of this genus also only one species is known hitherto, Xenopus Bojei Wagl., 

 Dactylethra capensis Cuv., Dum. and Bibr., Cuv. R. Ani., sec. ^d., PI. 7, 

 fig. 3, C. Mayer Analecten f. vergl. Anat. 1835, Tab. 11. figs. 5, 6, pp. 29 

 — 35, Dactylethra Delalandii Cuv. R. Ani., ed. ill., Rept. PI. 38, fig. 2, at 

 the Cape of Good Hope and the coast of Mozambique. 



Like Salamandra tmguiculata in the preceding family, Xenojnis amongst 

 the frogs is the only example of the presence of claws, which occur no- 

 where else amongst the Diplopnoa. The skeleton of Xenopus has much 

 resemblance to that of Pipa, especially in the pelvis ; the transverse pro- 

 cesses of the sacrum are triangular plates, with the apex turned inwards, 

 which afford a broad attachment for the iliac bones. In Pqoa and 

 Xenopus the two Eustachian tubes terminate in a small common oj^ening 

 in the middle of the ridge behind the palate. The membrane of the tym- 

 panum is cartilaginous. 



