Biologisches Centrallilatt. 



Unter Mitwirkung von 

 Dr. K. Goebel und Dr. R. Hertwig 



Professor der Botanik Professor der Zoologie 



in Münclien, 



herausgegeben von 



Dr. J. Rosentlial 



Prof. der Physiologie in Erlangen. 



Vierundzwanzig Nummern bilden einen Band. Preis des Bandes 20 Mark. 

 Zu beziehen durch alle Buchhandlungen und Postanstalten. 



Die Herren Mitarbeiter werden ersucht, alle Beiträge aas dem Gesanitgebiete der Botanik 

 an Herrn Prof. Dr. Goebel, München, Luisenstr. 27, Beiträge aus dem Gebiete der Zoologie, 

 vgl. Anatomie und Entwickelungsgeschichte an Herrn Prof. Dr. R. Hertwig, München, 

 alte Akademie, alle übrigen an Herrn Prof. Dr. Rosenthal, Erlangen, Physiolog. Institut, 



einsenden zu wollen. 



Bd. XXYIII. 1. Oktober 1908. >g 19. 



Inhalt: (jliild, Driesch's harmonic equipotential systems in form-regulation (Schluss). — Salensky, 

 Radiata und Büateria. — Mordwilko, Beiträge zur Biologie der Pllanzenläuse, Aphididae 

 Passerini. — Heg! und Dunzinger, Illustrierte Flora von Mitteleuropa. — Tigerstedt, Handbuch 

 der physiologischen Methodik. — Pappenheitn, Folia haematologica und Folia serologica. 



Driesch's harmonic equipotential systems in 



form-regulation. 



C. M. Child. 



(Sclihiss.) 



B. Proportionality in Relation to Position. 

 As regards the proportionality of primordia from different 

 regions and poles, I showed (Child, 1907b) that in primordia form 

 different regions and poles of the stem typical differences in pro- 

 portionality exist. These differences consist in differences in the 

 relative lengths of different parts of the primordia and may reach 

 almost 507o (cf. Child, 1907 b, p. 427, Table XIII and adjoining 

 text). To take a concrete example : The distal tentacle-area (area II) 

 is about 48 *'/(, longer in aboral primordia from the extreme proximal 

 regions of long stems, than it is in oral primordia from the extreme 

 distal region of the same stems. In the same cases the proximal 

 tentacle area (area IV) is 31 ^/^ longer in the aboral proximal than 

 in the oral distal primordia. Other examples may be found in the 

 table referred to. 



Such differences are not merely chance or irregular differences, 

 but are characteristic, and typical in direction, and their amount 

 depends chiefly on the distance in the original stem between the 

 regions where the primordia compared are formed and on the polar 

 position of the primordia. Moreover, these differences cannot be 

 XXVIII. 89 



