178 LIFE BY THE SEASHOEE. 



with the lobster the tail is much shortened, relatively to 

 the cephalothorax, its muscles are greatly reduced, and in 

 short it is mechanically unfitted to function as an organ of 

 locomotion for more than a limited period. 



Among the other interesting points of structure shown 

 by Galathea are the following. The antenna are not 

 beneath the antennules, but at the outer side of them. 

 The peduncle of the antennules is long, and the flagella 

 extremely short. This it will be remembered occurs also in 

 Palinurus, and it is also found in all the forms above 

 Galathea. The antennal scale is absent, as in Palinurus. 

 As in Palinurus, further, the first abdominal segment bears 

 no appendages in the female, and very rudimentary ones in 

 the male, in Galathea this segment is indeed considerably 

 reduced, owing to the sharp flexion of the body at the 

 junction of thorax and abdomen. This flexion and 

 reduction is, of course, universal among the crabs, and is 

 of some interest because some naturalists would regard the 

 reduction as directly the result of the pressure exerted 

 during the bending process. But it is important to notice 

 that the first abdominal appendages have disappeared in 

 Palinurus before the bending of the abdomen has begun. 



Most of the above are characters indicating the approach 

 of Galathea to the crabs, in which these structural peculiar- 

 ities are further emphasised; but in addition Galathea shows 

 certain special peculiarities. Note especially the condition 

 of the last pair of legs. These are reduced to mere rods 

 with a terminal brush of hairs and rudimentary chelae, and 

 are habitually carried tucked underneath the gill-cover. 

 In the figure they are shown spread out. The gill-cover, it 

 will be noted, is no longer vertical, as in the crayfish, but is 

 now oblique in position, and separated from the shield by a 

 suture. The well-developed rostrum with spines character- 

 istic of the species should also be noticed, and the reduction 

 of the abdominal appendages, whose only function seems 

 now to be to carry the eggs in the female. 



Two species of Galathea are common on our shores. The 

 commoner is G. squamifera, while the larger, G. strigosa, is 

 more usually found in deeper water. 



The first-named species has a short rostrum ending in a 

 spine, and bearing four spines on each side, the last being 



