Z()()LO{;iCAL SOCIKTY BULLETIN 



remain visible for days and even weeks, upon 

 the glass. 



In making these observations no attempt was 

 made to record the exact rate of progress with- 

 in a given length of time, nor was any elfort 

 made to discover whether the distances covered 

 were actually continuous, or were interrupted 

 by shorter periods of inactivity. 



The stations indicated on the chart were 

 recorded at noon of each day when any move- 

 ment was observed. Xo observations were 

 made at night, but the position of the specimen 

 was examined the first thing in the morning 

 and the last thing in the afternoon. The 

 records for Sundays were made by the em- 

 ploj'ee in charge of the aquarium for the day. 



The common brown anemone {Metridium 

 marginatum) and the small striped anemone 

 {Sagartia luciae), both of which are common- 

 ly kept at tiie aquarium, are known to have 

 similar powers of locomotion, though they 

 seem to move more slowly and less frequently. 

 Professor C. W. Hargitt informs me that the 

 white-armed anemone, the subject of this 

 paper, is one of the most active of all the mi- 

 gratory anemones. It would be interesting to 

 make a comparative study of the migrations of 

 our three common species, but, judging by the 

 leisurely movements of this, the most active 

 species, a considerable amount of time and 

 patience would be required. * * * * 



Since the above was written the writer has 

 had the opportunity to note the movements of 

 two brown anemones (Metiidiiim marginatum) 

 in the same jar, and, so far as could be deter- 

 mined, under the same conditions as the white- 

 armed anemone whose movements are discussed 

 above. 



The first of these was about an inch across 

 the base, or twice the diameter of the white- 

 armed anemone. Its position was noted on 

 .\pril 7 when it was about six inches above the 

 bottom of the jar. The following table will 

 show the amount of travel: 



Date 



April 



After the last move the animal remained only 

 a few hours, when it let go of the glass and 

 fell to the bottom, a dist.-ince of about 7 inches, 

 alighting on one side. Here, after a couple 

 of hours spent in righting itself, it moved a 

 short distance to a pebble where it has remained 

 ever since apparently quite contented with its 

 surroundings. 



As shown by the above table the longest 

 journey was only l^;; inches. As in the case 

 of the white-armed anemone the wanderings 

 were devious, every new move being at a sharp 

 angle from the preceding. As a result, during 

 the ten emigrations which covered a total dis- 

 tance of 7'/,s inches and consumed, with periods 

 of rest, 80 days, the animal was at no time more 

 than 2^-; inches from its starting point at No. 

 1. The only time it succeeded in getting any- 

 where was when it let go and fell to the bottom. 



The second brown anemone studied was 

 larger, about 2 inches across the base. When 

 first noted it had just moved from a pebble to 

 the side of the jar at the bottom. It did not 

 move up the glass like the others, but traveled 

 in straight lines back and fortii with a portion 

 of its foot in contact with the bottom. 



The table gives the distances and dates of 

 the various moves: 



26 



The next day. June 17, the anemone left the 

 glass and moved to a ])ebble where it has been 

 ever since. 



The first two moves were to tlie right totaling 

 6'*4 inches. The direction was then reversed 

 and the animal continued toward the left until 

 it moved away from the glass. The longest 

 single days journey was 5^ ^> inches. This dis- 

 tance does not seem great, however, when we 

 consider that this anemone stretched itself out 

 in the direction of travel until its base was 2^^' 

 inches long. The total distance traveled in the 

 five moves was IOV4 inches, an average of 

 slightly more than 2 inches per journey. The 

 average distance traveled on days when any 

 aetivitv was noted was therefore about the same 

 for this large brown anemone as for the much 

 smaller white-armed anemone, though perhaps 

 the number of moves made by the former is too 

 small to afford .1 safe comparison. 



