114 DIVERSIONS OF A NATURALIST 



The name " Cirripedes " is commonly used for the 

 order or group formed by the barnacles — in allusion to 

 the plume-like appearance of their " raking " legs. Stalked 

 barnacles often are found in the ocean attached to float- 

 ing pumice-stone, and one species has been discovered 

 attached to the web of the foot of a sea-bird. They, like 

 many other creatures, benefit by being carried far and 

 wide by floating objects. Whales have very large and 

 solid acorn-barnacles peculiar to them, fixed deeply in 

 their skin. Others attach themselves to marine turtles. 



With few exceptions the crustaceans are of separate 

 sexes, male and female. But in nearly all classes of 

 animals we find some kinds, even whole orders, in which 

 the ovaries and spermaries are present in one and the 

 same individual. " Monoecious " or " one-housed " — that 

 is to say, possessing one house or individual for both 

 ovaries and spermaries — is the proper word for this 

 condition, but a usual term for it is "hermaphrodite." 

 " Dioecious " is the term applied to animals or plants in 

 which there are two kinds of individuals — one to carry 

 the spermaries, the male, and the other to carry the 

 ovaries, the female. It is probable that the monoecious 

 condition has preceded the dioecious in all but unicellular 

 animals. In vertebrate animals as high as the frogs and 

 the toads we find rudimentary ovaries in the male, and 

 in individual cases both ovaries and spermaries are well 

 developed. Such a condition is not rare as an individual 

 abnormality in fishes. In some common species of sea- 

 perch (Serranus) and others it is not an exception but 

 the rule. 



Many groups of molluscs are monoecious, and it is 

 not in any way astonishing to find a group of crus- 

 taceans which are so. The Cirripedes or barnacles are 



