278 PROFESSOR MARSHALL. 



the interval between inversion and completion of the righting manoeuvre 

 being about two and a half minutes. This experiment was repeated 

 many times with different specimens. Some righted themselves 

 instantaneously, others took a longer or shorter time, but the general 

 average of the times taken by eviscerated specimens to right themselves 

 was about half a minute longer than that of uninjured ones. 



This affords strong additional evidence that the co-ordinating centre 

 of the complex muscular movements of which an Antedon is capable 

 is situated not in the visceral mass, but in the calyx. 



C. On the Power of Regeneration of Eviscerated Si^ecimens. 



It has been stated above that an eviscerated Antedon not only 

 attaches itself by its cirri in a perfectly normal manner, but that it 

 may remain so attached for a week or more. On experimenting one 

 day with a specimen that had been eviscerated about a fortnight 

 previously, I noticed that it righted itself when inverted rather more 

 readily than is usual in eviscerated specimens ; and on examination I 

 found that very considerable regeneration of the visceral mass had 

 occurred. The soft tissues lining the calyx were of some thickness ; 

 a mouth was already present in the centre of the oral surface, and 

 ambulacra! grooves had formed converging from the arms to the 

 mouth. I at once took steps to secure a complete series of specimens, 

 showing all stages of this regeneration, and I hope to be able shortly 

 to describe the process in detail. 



That Antedon possesses this very extensive power of regeneration, 

 greatly exceeding even that of Holothurians, was an entirely new fact 

 to me. Dr. Carpenter tells me that he was led to suspect this long 

 ago, and he has very kindly shown me specimens that have been in 

 his possession for many years, which seem to me to be clearly cases in 

 which regeneration has been partially effected. Dr. P. H. Carpenter 

 also tells me he has known this fact for some time, though I believe 

 no notice of it has yet been published. It is only fair to add that 

 while at Naples the possibility that an eviscerated Antedon might 

 regenerate its visceral mass was suggested to me in conversation by 

 Dr. Orley, of Buda-Pesth. I made very light of the suggestion at the 

 time, and was much astonished when a few days later I found the 

 specimen described above. 



The influence of the nervous system on the regeneration of lost 

 parts is a point concerning which we know very little ; but the apparent 



