PLATE XX 



Fig. i. A large, preserved right-handed Physalia, float-length 20 cm., 

 from Villefranche, Mediterranean, by permission of Dr G. 

 Tregouboff, Museum, Station Zoologique, to show gonodendra 

 of a mature specimen. Cormidium 1 on the right, x o-6. 



Fig. 2. A mature gonodendron dropped by a living specimen in a 

 laboratory tank at Arrecife. Photographed (as in life) after 

 anaesthetization in MgCl 2 and fixation in formalin, and seen from 

 above, x 1-3. 



Fig. 3. One tripartite group of a cormidium of specimen Lanzarote, 

 no. 2. Of the eight gastrozooids, number 3 with a prominent kink is 

 probably the original one of the whole group, associated with the 

 tentacle; numbers 2, 5, 7 and 8, which are gonozooids without 

 tentacles, were budded from its base. The genital tufts (palpons, 

 nectophores, gonophores and jelly-polyps) are budded from the 

 bases of the gonozooids. For details, after removal of three branches, 

 see Text-fig. 25. x 11. 



Fig. 4. A young gonodendron from specimen Lanzarote, no. 2 from 

 basal branch A (branchlet 3) of cormidium II. The polyps whose 

 tips can be clearly seen are palpons; the long polyps are gono- 

 zooids (with no tentacles), x 4. 



Fig. 5. A gonodendron not fully developed, x 8. 

 Fig. 6. A mature gonodendron dropped by the same living specimen 

 shown in fig. 2, seen from the side, x 1-5. 



