2 14 



ANURA 



CHAP. 



tadpole is nearly ready to leave the water, its whole bulk is re- 

 duced to less than one-fifth that of the largest tadpole. It measures 

 from snout to vent only 1^ inch (in the 7-inch tadpole this 

 distance is fully 2 inches), and the tail, devoid of fins, is 

 reduced to 2 inches in length. Instead of the solitary left 

 spiracle there are now two, one on the ventral side and a little 

 in front of the base of each arm, the border of each hole being 

 continued by a peculiar semilunar fold. 



Hylodes. — The numerous species, nearly fifty, of this tropical 

 American genus exhibit several anatomical differences. The 



tympanum is sometimes indistinct 

 or hidden, in which case the 

 Eustachian 



very narrow, 

 and carry 

 which are 



tubes are generally 



The fingers are free, 



discs, like the toes, 



sometimes slightly 



webbed. The males have a sub- 



gular vocal sac, producing a loud, 



or whistling, voice. The general 



appearance is that of land- and 



tree-frogs ; the size is small, mostly 



between 1 and 2 inches. 



H. viartinicensis is about 1^ 

 inch in length. The ground- 

 colour is pale yellow -grey, with a 

 large brown patch on the nape, 

 which colour is continued over the 

 (After back in the shape of more or less 

 coherent or dissolved patches. A 

 dark brown stripe runs along the middle of the sides. The 

 limbs are barred with brown, the under parts are whitish. This 

 species, known by the vernacular name of " roqm'' inhabits many of 

 the West Indian islands, e.g. Barbadoes, Martinique, Porto Eico, and 

 Hayti. It has become famous, as it was the first instance known 

 of a frog which undergoes its whole metamorphosis within the 

 egg. The pairing takes place on land, in the months of May 

 and June, when the female lays about twenty eggs, which are 

 enveloped in a foamy mass and glued on to a broad leaf, or 

 hidden in the axillae of Iridaceous plants. The mother seems to 

 remain in the neitrhbourhood watchino- the eggs, which are 



Fig. 42. — Ilylodes martinicensis. ], 

 an egg with embryo about seven 

 days old ; 2, another, twelve days 

 old ; 3, the young Frog just hatched ; 

 all X 2 ; 4, adult male x 1. 

 Peters. ) 



watching 



