THE AQUARIUM, APRIL, 189(j. 



make their appearance. They are very 

 small and have the shape of tadpoles. 

 The father takes especial care of them, 

 keeps them together and wards off en-e- 

 mies, even attempting to attack moving 

 objects outside of the tank, looking 

 upon these as enemies coming to de- 

 vour his little ones. During the first 

 three days his object seems to be to 

 keep his young near the surface, where 

 they have abundance of air and where 

 he can see them all ; after that he scat- 

 ters them by blowing among them. He 

 is now seen very busy everywhere in 

 the tank, and often gathers some weak 

 ones with his mouth and spits them to 

 the surface. This may be to instruct 

 them how to breathe. 



As the young increase in size his duty 

 is to teach them how to find their food. 

 For that purpose he takes a mouth- 

 ful of young ones from a place which, 

 in his opinion, is too thickly settled 

 compared to the food supply, and car- 

 ries them to a less frequented spot in 

 the tank, where food is more likely to 

 be plentiful. In short, he has a system 

 about raising a crop of children. Dur- 

 ing all this time the female is kept in a 

 far-off corner. He does not allow her 

 to go near the nest, although we have 

 never seen a female injure any of the 

 young, which were sometimes close 

 around her, some even nibbling at her 

 mouth. When the young are ten or 

 twelve days old, they liave the shape of 

 the old ones and can support tbem- 

 selves. They are then one sixteenth of 

 an inch in length. At this period the 

 male builds a new nest and. a new crop 

 of young ones is raised ; this is followed 

 by a third and fourth, until the ap- 

 proach of cold weather puts a stop to it. 

 We have had as many as twelve dif- 

 ferent broods from one pair in one 

 summer. Under favorable circum- 



stances the paradise fish will attain 

 their full growth at the age of one year, 

 when they will be ready to breed. The 

 limit of their life seems to be five 

 years, as we have not been able to keep 

 a pair longer than that. This fact 

 seems to be another proof that the 

 natural life of an animal, man included, 

 is five times as long as the period re- 

 quired to attain full development. 



DEVELOPMENT OF THE FROG. 



Frogs, toads, tree-frogs, newts, sala- 

 manders, 231'oteans and sirens are called 

 batrachians. This class of animals 

 ranks between the reptiles and the 

 fishes, and is subdivided in tailed and 

 tailless batrachians. The body of every 

 member of this class is covered with a. 

 naked, moist skin ; all those belonging 

 to the tailless division breathe through 

 lungs and their skin. They hibernate 

 during the winter on the bottom of 

 ponds or near springs, and during that 

 time take no food. 



With very few exceptions all the 

 batrachians deposit their eggs, called 

 spawn, in the water, from which, after a 

 longer or shorter period, a larva hatches- 

 which is known as tadpole. This tad- 

 pole is from the beginning of its exist- 

 ence independent of its parents. It 

 finds its own food and gradually passes 

 through various stages of development 

 until it has finally attained the shape of 

 its parents. The duration of this devel- 

 opment differs in the different species 

 and climes, some completing it in a 

 few weeks, others requiring months, 

 while there are some that require a year 

 or even longer to change to their final 

 forms. 



The excej^tional cases mentioned 



above, where the spawn is not deposited 



"into the water, are the fire- salamander 



