SEA-FAN MAKERS. 199 



From him we learn that the members of a coral 

 association are either males, females, or hermaphro- 

 dites. Ordinarily, the greater number of polypes on 

 one branch are of the same sex ; one branch con- 

 taining almost exclusively males, another females ; 

 the hermaphrodites are the least numerous. The 

 coral polyp is viviparous that is, the ggs become 

 embryos before they leave the parent. The eggs 

 have long slender pedicles ; they come out of the 

 thin layers which line the digestive bag ; they are 

 spherical, opaque, and of a milk-white colour. They 

 detach themselves by breaking their pedicles, and 

 thus fall into the central cavity of the polyp, a cavity 

 which serves as a stomach and an incubating pouch. 

 Here two very different processes are in action, the 

 one dissolving the food and nourishing the animal, the 

 other developing and producing a new creature. In 

 due time the eggs lengthen, and vibratile cilia appear. 

 As soon as they are born that is, vomited a pore 

 opens at one of the extremities, which is destined to 

 become the mouth. Then they assume the form of 

 a whitish semi-transparent worm. These larvae swim 

 in all directions, with the greatest agility ; they rise 

 and sink in the vases which contain them, always 

 swimming with their thicker extremity in advance, 

 carrying their mouths in the rear, so that they butt 

 against anything which happens to be in their way. 

 They have a tendency to become fixed, like their 



