62 



Crayfish, I suggested to my father that it would be a good opportunity 

 for me to try and reconcile the differences between his own observations 

 and those of Professor Semper, who would probably still have in his 

 possession the sections which he had made in the Philippines and had 

 used as the basis of his descriptions. The idea of making a deliberate 

 attack on the work ofM. Perrier, with which I Avas, even then, most 

 imperfectly acquainted, never presented itself to me at all. For I knew 

 that my father was preparing a memoir for the Royal Society, which 

 would at once vindicate the truth of his previous descriptions and ex- 

 pose the errors into which Perrier had fallen. 



Upon my arrival in Würzburg, Professor Semper at once acceded 

 to my request for permission to see his sections, Avhich he kindly placed 

 in my hands for re-examination; and he was good enough also to put 

 at my disposal various pieces of the arms of his Philippine Comatula 

 which I could cut for myself. I need not go into the whole question 

 again. It is sufficient to say that the differences between my father's 

 results and those of Professor Semper were reconciled in a manner 

 satisfactory to both parties. But the further observations which I was 

 thus enabled to make upon the structure of the arms in the Philippine 

 species seemed to indicate that it presented a most excellent field for 

 inquiry. Professor Semper generously placed at my service all his 

 examples of this particular type, the investigation of which occupied 

 my whole time for many months, and led to the entire abandonment 

 of my original plan of Avork for the winter of 1875 — 1876. 



(Schluß folgt.) 



2. Über den Bau und die Entwicklung von Heterodera Schachtii Schmdt. 



(Vorläufige Mittheilung.) 



Von Ad. Strubell, stud. rer. nat. aus Frankfurt a/M. 



(Schluß.) 



Das Ei unserer Heterodera besitzt die Gestalt einer Bohne oder 

 Niere und wird von einer zarten Dotterhaut und einer derberen, struc- 

 turlosen Schale umschlossen. Die Dotterelemente sind sehr groß, was 

 den Einblick in die Umbildungsprocesse beträchtlich erschAvert. Die 

 EntAvicklung hebt bereits im Uterus an, avo man Eier in den ver- 

 schiedensten Furchungsstadien antrifft. Hinsichtlich einer genaueren 

 Schilderung der Klüftungsvorgänge, Avie auch bezüglich der weiteren 

 embryologischen Details verAveise ich auf die ausführlichere Arbeit. 

 Hier sei nur bemerkt, daß ich bei Heterodera eine so gesetzmäßige 

 Verlagerung der Blastomeren, die, wie Halle z neuerlich behauptete, 

 bei allen Nematoden die gleiche sein soll, nicht beobachten konnte. 



