152 THE AFKICAN BULL-FKOG. 



of the Frogs is greatly affected by the locality in which they are at the time placed. The 

 Tree-Frogs are more subject to this change, of colour than the ordinary species ; but even 

 our common English Frog is well known to alter from yellow to brownish black in a very 

 short space of time. This change is produced by some mental emotion acting upon certain 

 masses of pigment or colouring matter in the skin ; and for a farther elucidation of the 

 subject, I must refer the reader to my " Common Objects for the Microscope," where the 

 pigment masses are drawn as seen through the microscope, and their peculiar action 

 explained. 



ONE of the most singular members of this group of animals is the PARADOXICAL FEOG 

 ( Pseudis paradoxa). 



This curious creature is a native of Surinam and South America, and is remarkable for 

 the enormous size of the larva, or tadpole. As a general rule, and indeed, as might 

 be expected, the generality of the batrachians are smaller in their larval than in 

 their adult state ; the tadpole of the common Frog being a good example. But the 

 Paradoxical Frog exhibits a phenomenon which is perhaps found in none of the higher 

 animals, though common enough among the non-vertebrated beings, and is less in its 

 adult state than in its preliminary form of tadpole. 



The tail of this tadpole is exceedingly voluminous, and the body has other envelopes 

 or appendages, which, when thrown off as it proceeds to its perfect state, reduce the bulk 

 so greatly that the earlier observers thought that the creature reversed the usual order of 

 nature, and from a Frog became a tadpole. Some persons went even farther, and said that 

 it was changed from a Frog into a fish. The appropriate title of Paradoxical was given to 

 it in allusion to this opinion. 



Strange, however, as this phenomenon may appear, and remarkable as it undoubtedly 

 is, it finds abundant parallels in the insects, where the larva is often of greater bulk than 

 the perfect insect, or imago, as it is technically called. We may take for example the 

 common silkworm, where the caterpillar is extremely large when compared with the moth 

 into which it afterwards changes ; or that great, fat, bulky, subterranean grub, which eats 

 continually for three years, becomes so obese that it is forced to lie on its side, and 

 afterwards turns into the neat, compact, and active little cockchaffer. 



The colour of the Paradoxical Frog is greenish, spotted with brown, and streaked 

 irregularly with brown along its legs and thighs. The snout is tapering, and rather pointed 

 in front. 



OUR next example of the Banidse is the AFRICAN BULL-FROG. 



This fine species is spread over the whole of Southern Africa, but is found most plenti- 

 fully towards the eastern coast, where it always frequents springs, pools, or the vicinity of 

 fresh water. It is most impatient of drought, and when a more than usually dry season 

 has parched the ground and rendered the hot soil uncomfortable for the delicate skin of 

 the creature's feet and abdomen, these Frogs are said to congregate in the pools in great 

 numbers, and just before the water has quite dried up, to burrow deeply into the soft mud 

 and there lie until the next rains bring the welcome moisture. 



Fifty of these large Frogs have been seen gathered together in one little pool, far from 

 any other water. It is, moreover, evident that they must have some place of concealment, 

 for they are sure to appear in great numbers after a few heavy rains, and it is quite con- 

 sistent with probability that they should possess a simple and obvious method of preserving 

 their lives during the frequent droughts of the climate in which they reside. 



Dr. Livingstone mentions this fine species in his well-known work on Southern Africa. 

 " Another article of which our children partook with eagerness was a very large Frog, called 

 ' Matlametlo.' 



These enormous Frogs, which, when cooked, look like chickens, are supposed by the 

 natives to fall down from thunder-clouds, because after a heavy shower the pools which 

 are filled, and retain water a few days, become instantly alive with this loud croaking 

 pugnacious game. This phenomenon takes place in the driest parts of the desert, and in 

 places where to an ordinary observer there is not a sign of life. 



