144 Transactions of the Boyal Society of Victoria,. 



to the inner, that the direction of movement would be the 

 same, but it is just the reverse of the inner of the same side. 

 Thus the right rotated to the left, or outwardly, while the 

 left rotated to the right, also outwardly. While this is the 

 normal direction, 1 observed that it was occasionally 

 reversed. This change might last for a few rounds, and 

 then the original normal direction woidd be resumed. That 

 the direction can be changed, and the original resumed 

 again is rather an important observation, showing that 

 the arrangement is not altogether a mechanical one, which 

 causes the palps to move in a particular direction, like the 

 hands of a clock. 



The rate happened to be more regular than in the inner. 

 This is evident from the fact that I was able to observe 

 their movements over extended periods of time and through 

 a number of rounds (50) without their movements becoming 

 feeble or sluofsrish. 



Left — The left was observed for 20 rounds moving to the 

 right with great regularity. The average was 7J minutes 

 to the round, the slowest being 9 J minutes, and the quickest 

 6 minutes. It commenced at the rate of 6 minutes per 

 round, and with a steady pace, varying from 6 to 9 minutes. 

 The 20th round was performed in 7 J minutes. The move- 

 ment still continued when I ceased recordino-. 



Right. — The right was observed continuously for 50 

 rounds, and for given periods of time the rate was pretty 

 constant. The general average was 5 minutes to the 

 round; the slowest i-ecord was at the commencement, with 

 25 minutes to the round, and the quickest was 2 minutes. 

 The partial average for the 20 best continuous rounds, from 

 the ISth to the 32nd inclusive, was 3 minutes, and the 

 middle round of the whole (25th) was 2 minutes. The palp 

 was going at the rate of 4 minutes to the round, when I 

 left off observing, and the 51st round took -5 J minutes. 

 Both left and rio^ht continued to move for some time after- 

 wards, as I observed them for 25 minutes rotating as usual. 



In this series of observations, extendino- over 4 hours, 

 there was no variation in the direction, the left always 

 revolving to the right, after being fairly started, and the 

 right always to the left. But in a second continued series 

 of observations, there was considerable variation in the rate 

 and regularity, and a change in one of them once in the 

 direction of movement. 



