300 



ZOOLOGY 



SECT. 



(From 



FIG. 967. Nototrema marsupiatum . 



Female, with pouch opened. 

 Mivart.) 



condition are formed of segmentally arranged portions, each with 

 a nephrostome and a glomerulus, as in Myxinoids (see p. 137). 

 A pronephros is present in the larva, but disappears in the adult. 



A urinary bladder is almost always 

 present, opening into the cloaca 

 and having no connection with the 

 ureters. In some Gymnophiona 

 the cloaca can be protruded and 

 acts as a penis. 



Reproduction and Develop- 

 ment. External impregnation 

 takes place in Anura, but in many 

 Urodela the sperms are aggregated 

 into spermatophores by glands in 

 the wall of the cloaca, and these, 

 being deposited on the body of the 

 female, are taken into the cloaca 

 and effect internal impregnation. 



Several curious instances of 

 parental care are known. A 

 number of different species of Frogs 

 and Toads construct nests or 

 shelters of leaves or other materials in which the eggs are 

 deposited and in which the young are developed. In the Obstetric 

 Toad (Alytes obstetricans) of Europe the male winds the strings 

 of eggs formed by the adhesion of their gelatinous investment 

 round his body 

 and thighs, where 

 they are retained 

 until the tadpoles 

 are ready to be 

 hatched. In 

 Rhinoderma dar 

 wini, a little South 

 American Frog, 

 the eggs are trans- 

 ferred by the male 

 to his immense 

 vocal sacs, which 

 extend over the 

 whole ventral sur- 

 face, and there 

 hatched. In an- 

 other Anuran, 

 Nototrema (Fig. 967), there is a pouch on the back of the female in 

 which the eggs are stored, the young being hatched in some species 

 as tadpoles, in others in the adult or Frog form. In the Surinam 



FIG. 968. Fipa americana. Female. (From Mivart.) 



