No. 447-] BRHHDLW; }IAIUTS OF rRAVI-lsll 



Observations were discontiiuied with tlic animal upon ilu- ven- 

 tral side at 5.50 p. m. In this lono- scries iheiv is only oiu' bri'ak 

 in the rhythm at the point marked x wlien atU'r ;i iinmiti's ot 

 turning in which there were ten alternations honi iii;ht to li-tt ; 

 the female then walked about the dish as it srekm- some c (h iut 

 more retired than the one she finally returned to and reniamed 

 in to make the following ten alternations. 1 his walkmu a\\a\ 

 from the corner otherwise so closely kept accounts lor the loiii; 

 interval of eleven minutes on the ventral side m piaec- ot the 



break in the close sequence, the turning upon the lett side when 



the time factor to be so dominant as to cause the ieinale to go 

 over to the lett side after eleven minutes because that would 

 have been time enough for, say, a ventral rest of 2 minutes, a 

 right rest of 7^ and a left of which would bring the period 

 around again to a left rest as next in order. At the pomi 

 marked f the ventral time is abnormally lengthened as it 

 includes the minute and a half spent by the female in strug.i;lin,^ 

 together ventral position after accidentally rolhn- o\ei upon 

 her back from the position on the right. 



The result attained by this performance would seem to he the 

 proper fastening of the eggs to the pleopods, without uhkh the 

 eggs would not develop. During this proeess the temale sta\s 

 in one corner of the dish and except when tuinm.i; tiom one 

 position to another lies so still that it might be taken toi dca^l , 

 only rarely were any of the claws reached near t<. the abdomen 

 and there is no evidence of any manii)ulation to seiuie the 

 attachment of the eggs within the abdominal basket, it is well 

 known that ultimately each egg is firmly tied to the haiis ot the 

 pleopods (a few also to .some .sternal hairs) by a strong string 



sort of second shell. These strings and cases are gradually 

 formed, and from some of the cement gland secretions no doubt. 

 For twelve hours or more after the eggs are laid they may be 

 easily pulled away from the pleopods as they are stvick only by 

 a soft glair, but later this glair hardens and force is needed to 

 break the strings away from the pleopod hairs. In one case 



