148 ANURA 



CHAP. 



a few feet distance. The male grasps the female by the loins ; 

 the eggs are extruded singly, measuring only 1.5 mm. in diameter, 

 but swell to double that size. They are attached singly to stones 

 or water-plants. 



Latterly these creatures have frequently been brought over to 

 England. They stand confinement very well, even in a little 

 aquarium with sufficient water-weeds to keep the water fresh ; and 

 they do not require special heat. They greedily snap up worms, 

 strips of liver, or meat, and poke the food in with their hands. 

 A few kept by Boulenger in a glass jar have lived for the last 

 eleven years in the ordinary temperature of a room in London. 

 Curiously enough they are often in amorous embrace, regardless 

 of the season, but they have never shown any signs of spawning. 



Some of those in the Zoological Gardens in London laid eggs 

 on Saturday the 27th of May, and on the morning of the follow- 

 ing Monday the larvae were already hatched. They have been 

 described by Beddard. 1 The larvae are provided with an unpaired 

 circular, ventral sucker. The tentacles begin to sprout out on 

 the sixth day after hatching, at first not in connexion with the 

 cranial cartilage, but soon a cartilaginous rod runs into the 

 tentacle from the ethmoid "just above the joint with the under 

 jaw." Boulenger has most reasonably compared these organs 

 with the "balancers" of Triton and AmUystoma (cf. p. 46 for 

 the possible homologies of the balancers). The tentacles soon 

 reach a great length and give the tadpole a curious appearance. 

 In tadpoles of X. calcaratus, 65 mm. long, the tentacles 

 are 30 mm. long, and are inserted just at the angle of the 

 mouth. By the time that these tadpoles show their fore-limbs, 

 the feelers are reduced to 4 mm. in length, and their relative 

 position has been shifted to a little above the angle of the gape, 

 and whilst the latter gradually extends further and further back, 

 the feelers come to lie, or rather remain, below and a little in front 

 of the eyes. 



The tadpoles have no traces of horny teeth. External gills 

 project as low conical or lamellar processes from the first three 

 branchial arches, but so-called internal gills are not developed. 



Amongst a number of Clawed Toads imported in the spring 

 one female became swollen with eggs, but as they did not show 

 signs of wanting to breed, a pair was put into the tropical tank 

 1 P.Z.S. 1894, p. 101. 



