I 20 



one develops sooner than the other. The medusiform gonocalyx differentiates itself first and 

 shows the limit of two divisions of the side-branch, the proximal consisting of the stalk with the 

 o^onophores, the distal of the gonopalpon. In PJiysalia three "Polypoide" are developed at the 

 same time with the medusiform gonocalyx; the proximal one develops into the gelatinous 

 polypoid (Gallertpolypoid) the two distal ones take the medusiform gonocalyx between them and 

 develop into gonopalpons. The gonophores develop only later. 



Comparing Chun's statements with our material we found the following differences. 

 A well-developed gonodendron was taken from the stem of a full-grown Physalia 

 (PI. XXIV, fig. 175). It showed six side branches, of which four were situated on the right 

 side, two on the left. The first two situated closest to the basal part of the common gonostyle 

 are situated on the right and left sides opposite to each other. They were called A (right 

 lateral branch) and B (left lateral branch). 



The other divisions of the main-branch are C, D, E to the right and F to the left. 

 The main-branch ends into the two terminal side-branches E and F. Moreover we find on the 



right side a palpon-like structure of which we 

 will speak later (see p. 121) and on the left a 

 gelatinous polypoid ; gonophores were also found 

 scattered on the main branch. 



For a further separation we chose the 

 side-branch D. (textfigure 52). 



B bifurcates at once into two .side-branches 

 B I on the right, B 2 on the left. Again it seems 

 that the further division oi B 2 is the most 

 normal one. 



It gives oft" three tertiary side-branches 

 all situated on the left side. So here there is no 

 question of bifurcation. These branches (/? 2 a, 

 B 2 d, B 2 c) all subdivide again as follows: B2a 

 divides into B 2aa, B 2 ad and B2ac. 



And it is only now that we can distinguish 

 the different constituents of the gonodendron ; 

 B 2 aa namely shows a proximal part [B 2 aa I') 

 consisting of one gonopalpon, 5 gonophores and 

 the very .same gelatinous polypoid. Chun speaks 

 of its basal part being imbedded in the gelatinous 

 and muscular substance of this side-branch of the 

 gonostyle. The distal part oi B 2 aa is B 2 aa I" 

 and consists of one gonopalpon eight gonophores and a long stalked, medusiform gonocalyx. 



B 2 ad .shows absolutely the same amount of appendages that is to .say: B 2 ad I' shows 

 one Gallertpolypoide, a gonopalpon, 8 gonophores, and J> 2 ab I" consists of one palpon, one 

 medusiform gonocalyx, 8 gonophores. 



Kig. 52. riiysalia ulriciiliis Lamaitinicie. 



.\ diagrammatic sketch of the subdivision of a side-branch 



in a fuUy-developcd gonodendron. 



