SUEINAM TOAD. 29 



odd : tlie bead is flat and triangular, a yery short neck sepa- 

 rates it from the trunk, which is itself depressed and flattened. 

 Its e^'es are extremely small, of an oliye, more or less bright, 

 dashed with small reddish spots. It has no tongue. There is 

 only one species of Pipa, yiz. the American Pipa (Fig. 8), which 

 inhabits Guiana and seyeral provinces of Brazil. The most 

 remarkable feature in this Batrachian is its manner of reproduction. 

 It is oviparous, and when the female has laid her eggs, the male 

 takes them, and piles upon the back of his companion these, 

 his hopes of posterity. The female, bearing the fertilized eggs 

 upon her back, reaches the marshes, and there immerses herself ; 

 but the skin of the back which supports the eggs soon becomes 

 inflamed, erysipelatous inflammation follows, causing an irritation, 

 produced by the presence of eggs, which are then absorbed into 

 the skin, and disappear in the integument until hatched. 



The young Pipa Toads are rapidly developed in these dorsal 

 cells, but they are extricated at a less advanced stage than almost 

 any other vertebrate animal. After extrication, the tadpole grows 

 rapidly, and the chief change of form is witnessed in the gills. 

 As to the mother Batrachian, it is only after she has got rid of 

 her progeny that she abandons her aquatic residence.* 



The Batrachians differ essentially from all other orders of Rep- 

 TiLiA. They have no ribs ; their skin is naked, being without scales. 

 The young, or tadpoles, when first hatched, breathe by means of 

 gills, being at this stage quite unlike their parents. These gills, or 

 branchiae, disappear in the tailless Batrachians, as the Frogs and 

 Toads, in which the tail disappears, are called. In the tadj)oles the 

 mouth is destitute of a tongue, this organ only making its appear- 

 ance when the fore limbs are evolved. The habits also change. 

 The tadpole no longer feeds on decomposing substances, and cannot 

 live long immersed in water. The branchiae disappear one after the 

 other, by absorption, giving place to pulmonary vessels. The prin- 

 cipal vascular arches are converted into the pulmonary artery, and 

 the blood is diverted from the largest of the branchiae to the limgs. 



* The same phenomena occur, with certain variations, in some other American 

 Batrachians, as the Nototrenia marsupiatttm of Mexico, and the Notode^phys ovifera of 

 Venezuela. In the Ahjtes obstetricaiis of France, Switzerland, and the Ehine 

 district, the ova (about sixty in number) adhere to the hind-legs of the male parent ! 

 —Ed. 



