THE DECAPOD CRUSTACEA. 181 



the last pair of legs is modified to form two slender rod-like 

 structures, habitually kept folded beneath the lateral margin 

 of the carapace, and terminating in minute chelae with a 

 brush of hairs. In the figure they are represented in the 

 unfolded condition. Besides the terminal swimmerets, the 

 abdomen in the female bears four pairs of slender hairy 

 appendages used for carrying the eggs, -while in the male 

 there is only a single pair of slender rods. The reduction 

 of the abdominal appendages in the male should be noticed, 

 as it is very characteristic of crabs compared with long- 

 tailed forms. The appendages of the male belong to the 

 second abdominal segment, and the appendages of the first 

 segment are also absent in the female, as in crabs. The 

 porcelain-crabs are passive little creatures as a general rule, 

 showing marked preference for secluded situations, and 

 clinging tightly- to stones or weed when disturbed. In 

 spite, however, of the crab-like appearance, they still retain 

 the power of swimming, as may be often seen in captivity 

 in the minute porcelain-crab. Occasionally this species 

 gives up its sedentary habits and takes to active swimming 

 through the water. The motion is, of course, backwards, 

 and it is very curious to notice that although it begins its 

 journey in the normal position, the weight of the heavy 

 claws seems to invert the body, and it very speedily falls 

 over on its back. It is a very interesting sight to see the 

 little creatures lying on their backs in the water and 

 propelling themselves backwards by vigorous jerks. It is 

 obvious that under such circumstances the long antennae 

 are of much use in helping to direct the movements and 

 avoid collisions. I have never seen the hairy porcelair- 

 crab swim, and if it does so the heavier claws must hand'- 

 cap it considerably, and make tbe movement exceedingly 

 fatiguing. The whole shape of the claws is considerably 

 more crab-like than in the other species, and from the 

 nature of its habitat one would not expect that swimming 

 would be frequently indulged in. Both it and the smaller 

 species, when turned on their backs, flap their tails to assist 

 their efforts to regain the natural position. In specimens 

 kept in confinement the dense fringe of hairs on the third 

 maxillipedes should also be noticed. In the hairy porcelain- 

 crab the hairs are used as a comb to clean the antennae and 



