103 



hat er neue Untersuchungen angestellt. Ueber die zwei ersten muss ich mich in 

 Rücksicht auf seine Bemerkungen hier äussern ; der dritte ist im XIV. Abschnitt 

 erledigt. 



1) Der erste Differenzpunkt, betreffend den Sitz der lokomotor ische n 

 Centren, bedarf, trotzdem er einer Ausgleichung nahe geführt ist, noch einer Er- 

 läuterung. Rom an es wiederholt den im letzten Jahre von ihm ausgesprochenen, 

 auf Seite 33 von mir citirten Satz, wonach die Otolithensäckchen der Sitz der Con- 

 tractionsthätigkeit sein sollen und erklärt dann , dass eine grosse Anzahl von neuen 

 Experimenten diese seine vorjährigen durchaus bestätigt haben l ). Dass jetzt in 

 „I was able to satisfy myself that the whole spontaneity of the lithocyst appeared 

 to be exclusivly lodged in the minute sac of crystals'- hinter „lodged in'- die Wörter 

 „or about" eingefügt sind, ist für die Frage nicht wesentlich. Romane s sagt: 

 „In no one instance have I been able to detect any physiological evidence of the 

 presence of ganglionic matter in the „contractile zones." In most instauces, of 

 course , occasional contractions were given after removal of the lithocysts alone; 

 but I was never able to observe that the spontaneity in these instauces proceeded 

 more exclusively , or more frequently , from the contractile zones than from any 

 other part of the general contractile tissue. For after allowiug the animal to recover 

 from the shock consequent upou removal of its lithocysts alone, and then observiug 

 the degree of spontaneity it manifested , I was in no case able to perceive that by 

 now removing all the contractile zones, this degree of spontaneity was in the smal- 

 lest degree dimiuished." In der Nachschrift 2 ) bemerkt er dagegen: „Lastly, the diffe- 

 rence of opinion which existed between us with regard to the exact seat of spon- 

 taneity in the covered eyed Medusae has also been happily removed. It appears 

 that I have hitherto been under some misapprehension as to the precise area of 

 tissue which Dr. Eimer intended to denote by his term „contractile zone"; for 

 while I have hitherto supposed that by the term „contractile zone" Dr. Eimer 

 intended to denote „the crescent-shaped interruption of the margin in which the 

 lithocyst, together with its gelatinous hood, is situated", I now learn that I was 

 incorrect in this supposition. From Prof. Eimer's letter I do not quite recognize 

 the precise tissue-area which he endeavours to describe as the area to which his 

 term „contractile zone" is applicable; but this is a matter of no moment, as he 

 leaves no doubt that the area in question is confined to what I may call the micros- 



1) Seite 661. 



2) Seite 751. 



