THE DECAPOD CRUSTACEA. 



177 



somewhat resembles a very short and broad spiny lobster. 

 The colour is variable, but in the commonest species, 

 G. squamifera, which attains a length of about three inches, 

 the prevailing tint is usually brownish blue. Very young 

 specimens are, however, not infrequently brilliantly marked 

 with bright blue and red. 

 In marked contrast to 

 Palinurus, we find that 

 Galathea is furnished with 

 a pair of long chelipeds, 

 forming the first pair of 

 legs. In so far it resembles 

 the true lobster and cray- 

 fish, but it will be noticed 

 that only the first pair of 

 legs bear forceps, not 

 several pairs, as in cray- 

 fish and lobster. With 

 the gradual increase in 

 the creeping habit, and 

 the diminution of the 

 power of swimming, the 

 next two pairs of legs 

 take on as their primary 

 function that of support- 



ino- thp hnrlv inrl ln?p FlG - 51 Scaly squat-lobster (GaZaMea squami- 



oay, ana lose /gra) The ^^ is figure v d in a som ^ ew hat 



their power 01 prehension, unnatural position, in order to show the 

 TVin ehirlpnf VrmlH nlr> structure of the tail, and afford a basis of 

 me Student snouia alSO comparison with the lobster, Fig. 48. 



not fail to notice that 



with the broadening of the body, first obvious in Galathea, 

 the insertion of legs also moves outwards, so that the body 

 becomes more definitely adapted to the creeping habit. It 

 may, however, be objected that it is not obvious in what 

 respects Galathea shows a diminished power of swimming, 

 in view of the frequent difficulty in effecting its capture. 

 That it is not so good a swimmer as the true lobster can yet 

 be proved both from structure and habit. As to habit, 

 Galathea habitually creeps on its walking legs, and only 

 darts backwards on the sudden advent of danger. In 

 repose it keeps the tail bent a trifling point, but one 

 fruitful in consequences. Then as to structure, compared 



N 



