11G ALONG THE FLORIDA REEF. 



dropped over the side of the boat. Diving 

 down, he inserted his hand under them and 

 brought several to the surface. 



" This is an interesting find," said the doctor 

 as Harry clambered into the boat with his prize. 

 " They are called sea-squirts, from their habit of 

 ejecting water. They seem to occupy a position 

 in life between the worm and the lowest back- 

 boned animals. These specimens are what we 

 call ascidians, and they have a most accommo- 

 dating heart, that, when tired of beating one 

 way, stops, and goes the other, so to speak, 

 throwing the blood in the other direction. Per- 

 haps you can remember them by that/' 



" Hallo, there are the coral-heads ! " cried 

 Tom, who was now poling with his grains in 

 the bow. 



" These can't be coral-heads, here," said the 

 doctor, as he looked toward the black spots in- 

 dicated 1 >y Tom ; and then he added : " I thought 

 as much. They are black sharks, or nurse, as 

 they are called. Keep quiet, and we can go di- 

 rectly among them. If there is a small one, we 

 might try to catch it." 



