266 



THE INFANCY OF ANIMALS 



commonly gaily coloured. 



on our coasts, where they form encrusting masses of 

 leathery consistency, and no particular shape, though 



When touched they will 

 generally expel a jet of water 

 — hence the name sea-squirt. 

 There are also free-swim- 

 ming species, and species 

 which grow in colonies, some 

 in pear-shaped lumps of a 

 blood-red colour, others of a 

 beautiful rose-pink spotted 

 with white, and resembling 

 a strawberry. It is not of 

 the adults, however, but of 

 their offspring that we are 

 to speak. These are hatched 

 within the body of the parent, 

 and for a time are packed 

 within the breathing chamber. 

 Eventually, however, they 

 escape from what we may 

 call the maternal apron- 

 strings, and emerge — in the 

 guise of tadpoles 1 Could 

 anything more surprising be 

 conceived, having regard to 

 their origin ? 



This is no fanciful resem- 

 blance, as a reference to our 

 illustration will show. The brain, eye, gills, tail, and the 

 rudiments of a backbone are all plainly visible. But it 

 resembles the unfinished, newly-hatched tadpole in that the 

 mouth is not yet open, and in that «he eye has not yet 



A LESSON IN DEGENERATION. 



B, C, D, 15 show the several stages 

 of physical degeneration displayed by 

 many of the sea-squirts. A=the tad- 

 pole of a frog for comparison with B, 

 which shows the larval stage of a sea- 

 squirt at its maximum development. 

 C, D, E are successive stages in de- 

 generacy. 



