ob New Species of Batracian Reptiles. 
trom ihe male. Concerning the rapidity of the mctamorphosé 
of these reptiles, Mr. G. Guvier has only remarked, “On 
sait que la Jackie (Rana paradoxa) ne perd sa queue que 
fort tard et long tems apres ses branchies, et que ses branchies 
clle-méme ne tombent que quand elle a déja sa taille de 
grenouille.”” (Sur les Animaux douteux Voy. de M. Hum- 
boldt.) 
Jt is very probable that the period required for the meta- 
morphose varies with the species. In the larve of the Rana 
pipiens, which we detained, expressly for examination, for 
more than two months, no sensible alteration was observed 
in this respect, or scarcely any visible approach towards per- 
fection. 
Numerous opportunities occurred to corroborate the re- 
mark of Mr. Cuvier, that the organs of generation exis‘ 
nearly in a perfect state in the larve of the frog. ‘‘ Among 
the many changes (continues Mr. Cuvier) to which the tad- 
pole is subjected in-its passage to a state of perfection, we 
cannot include the appearances of the organs of generation. 
We already observed the ovaries and their fatty appendages: 
and if they be not entirely as large as they are in the frog a! 
the epoch of its amours, they approach very near to what 
they are during the remainder of the year.” 
Agreeably to the observations of the author last quoted. 
‘‘ there are many species of tadpoles which have but one oper- 
culum on the left side; such are the larve of the R. paradowa. 
and those of the brown toad; but those of the common frog 
(Rana temporaria, Linn.) appear to me to have two holes. 
both placed beneath.” 
This fact I have verified in all the tadpoles which J have 
subjected to examination: after dissecting great numbers of 
tadpoles, of different specics and at different ages, both before 
and after the appearance of their legs, in no instance was 
there observed more than one opening or operculum, and that 
always on the left side; though dissection at all periods de- 
monstrated the existence of gills or branchiz on both sides, 
covered by integuments.—“ Les seules darves ou tetards des 
reptiles batraciens, c’est a dire des salamandres et des grenou- 
illes, rainettes, et crapauds réunissent des branchies et des 
poumons, respirent a la fois, du moins pendant un certain 
temps, et l’air elastique en nature, et celui que contient l’eau, 
participent par conséquent, d’une maniere eégale, de la nature 
des animaux aériens et des animaux aquatiques, et peuvent 
