374 



METAZOAN PHYLA 





found in Brazil which makes a nest for its eggs and young at the bottom 

 of a pond, building a mud wall about it ; another frog found in Venezuela 

 carries its eggs and young in a shallow pouch on its back until the latter 

 are almost ready for metamorphosis ; and still another found in Java has 

 greatly enlarged feet, the toes being connected by webs, making it pos- 

 sible for the animal to glide or sail through the 

 air for a considerable distance. A curious little 

 tree frog found on the island of Martinique glues 

 its eggs to a leaf, where they form a foamy mass. 

 In this case development is practically completed 

 in the egg and there is no aquatic larval period. 

 Thus some of these forms have practically eman- 

 cipated themselves from any need of an aquatic 

 environment, though they must still Hve in a 

 moist locality. 



397, Apoda, — The Apoda, or ceciHans, some- 

 times called blmdworms, are generally distributed 

 in tropical and subtropical countries. They pos- 

 sess neither girdles nor limbs but have concealed 

 dermal scales. They burrow in the earth some- 

 what as does an earthworm and are not unlike an 

 earthworm in general appearance. The anal 

 opening is almost at the posterior end, there being 

 merely a rudiment of a tail. The eyes are also 

 rudimentary and practically functionless, but the 

 animal possesses a protrusible tentacle-hke organ 

 lying in a groove between the eyes and nose by 

 and is inverted in the means of which it feels its Way about. In one 

 action; the insect adheres type found in southern and southeastern Asia the 

 wMr'^^LtTeat^Tci female lays her eggs in masses in a shallow hole 

 is drawn back into the near the water and coils herself about them 



(Fig. 263). The larval stage is passed in the 

 egg, the larva possessing three pairs of external 

 gills which are lost when it hatches. This larva swims about in the 

 water for a while, coming to the surface for air, but at length the 

 gill clefts close, the tail fin is lost, and the animal becomes terrestrial, 

 leading a burrowing hfe. Some types of Apoda are viviparous. The 

 whole group is to be looked upon as the result of a very pronounced 

 degeneration. 



398. Food. — The food of frogs and toads is composed of any Hving 

 animals which they can secure, particularly worms and insects. These 

 are captured by means of the protrusible tongue, which can be extended 

 considerably beyond the margin of the mouth and which is covered by a 

 sticky secretion (Fig. 264). Some animals are also grasped by the jaws 



Fig. 264. — Showing the 

 manner in which a toad 

 takes an insect. The 

 tongue is extruded in an ex- 

 ceedingly rapid movement 



mouth. (Modified from 

 Dickerson, "Frog Book.") 



