248 Dwellers of the Sea and Shore 



sterlike crustaceans, or macrurans, have a relatively 

 small hind body. In the fiddler crab, which is a typical 

 example of the Brachyura, the cephalothorax, or the 

 fore body, is flattened and broader than it is long. The 

 small, flat, segmented abdomen is folded under the fore 

 body and fits in a depression, making it appear to ordi- 

 nary eyes as if the creature's entire body were one rigid 

 piece without a division of hind or fore body. As a 

 matter of fact, the abdomen, though invisible from 

 above and inconspicuous when the animal is viewed 

 from underneath, is a very important part of the crab's 

 anatomy. In the male it carries the external parts of 

 the sexual organs, while in the female it has on the 

 under, or what may appropriately be termed the inner, 

 side four pairs of prominent hairlike appendages called 

 the swimmerets. It is to the swimmerets that the ex- 

 truded eggs are attached, forming the spongy mass. It 

 may be added that the hind body of the male is com- 

 paratively narrow, whereas that of the female is very 

 broad; a feature that readily enables the determination 

 of an individual's sex, which is not always obvious in 

 the case of the males, who ofttimes have lost their dis- 

 tinguishing claw. 



f The eggs in reality are divided into eight clumps cor- 

 responding to the four pairs of swimmerets, but they 

 are so closely packed that they seem to form one 

 large group. The mass is flattish and seems to be 

 wedged solidly between the thoracic region and the 

 abdomen; its bulk is about that of a navy bean's. But 

 so small are the individual units that more than seventy- 

 five thousand are contained within this space. Herein 

 is the secret of the fiddler crab's persistence, who, de- 



