ANATOMICAL NOTES ON THE ' COMET ' OF LINCKIA MULTIFOJIA, LAMARCK. 73 



The breaking of arms may take place at various localities ; in some at 

 the very base of the disc (Fig. 2, B.), in others at a remote distance — 5 cm. or 

 more — from the latter. It may take place several times in one and the same 

 individual, and in consequence of it thgre are many spscimsns which bear 

 some — even all — arms showinp; different stages of regeneration. And more- 

 over, a secondary breaking may occur in the same arm at a new point in 

 the regenerated part. Among 27 large specimens having a disc, measuring 

 more than one centimeter in diameter I find 22 or 23 speciemens carrying 

 an arm or arms — sometimes all arms — broken or regenerated ; and among 

 10 small forms having a disc which measure less than one centimeter in dia- 

 meter, only two or three are ascertained to possess an arm partly regenerated. 

 This difference in large and small speciemens ma)% however, be explained by 

 a fact that the greater the age the more often are the chances of breaking. 

 At all events, these facts show a great frequency of the breaking of the 

 arms. 



According to Haeckel,^^' Studer seems to believe that in Labidiaster 

 radlosus, the spontaneous breaking of arms serves to empty its eggs. In 

 LlncJiia 7)1711 1 if ora this does not seem to be the case. In this species there 

 are some young having a rudimentary generative organ and yet bearing an 

 arm or arms partly regenerated. In my three speciemens with the fresh 

 wound, the generative organ in immature. Simroth^'^ has studied Schizogong 

 of Ophiactis virena and remarks : " Theilung und geschlechtliche Zeugung 

 ganz unabhiingig von einander ihren Weg gehen." The same seems to hold 

 true in the present case. There may exist some chances of breaking when 

 the generative cells are fully grown, yet when we consider the stractiire of the 

 generative organ as well as the mode of breaking such chances do not seem 

 to be utilized for fertilization. 



No one has yet observed the actual breaking of an arm, but that it is 

 spontaneous is no longer to be doubted, when we consider the great frequency 

 of breaking and the firmness, under ordinary conditions, of arms which are 

 not easily injured. An important suggestion of this problem is given by 

 the brothers Sarasin'-' who remark : "In dem Gefasse, worin uns die 

 Linckia gebracht wurden, waren stets einige isolierte Arme zu finden, die 



