1 lO 



of the p t e r a water is driven in and out o f t h e cavity o f t li e s i p li o n s and 

 so they act exactly as the nectophores in Physonecta. 



The tentacles increase in length, so do the gonodendra. The latter are always situated 

 near the base of the siphons. 



Between C and D 15,5 cm. of the stem was not sketched; some siphons have become 

 detached the mark of their implantation being left on the stem. The siphons are of the 

 same size as in C, but they alter their aspect more and more, as they gradually lose their 

 ptera, get more muscular at the top and the base and have a more marked aperture sur- 

 rounded by strong circular muscles. 



D. D has a length of 33 cm.; the stem is the same as in the foregoing parts, the siphons 

 have entirely lost their ptera and have become elongate tubular structures. They are implanted 

 on the stem at 4 cm. distance one from the other. In the inferior part of D we see a lower 

 space between two siphons. One of them has probably become detached. The gonodendra 

 are so far developed that one can see the different constituents, viz. clusters of androphores, 

 gynophores and gonopalpons. 



The distance left out between D and E measures about 42,5 cm. The stem which 

 up to this distance has always had a certain breadth, gets thinner, more thread-like, absolutely 

 white, no longer transparent. It resembles a thin white string. The siphons are separated by 

 longer distances, the tentacles still increase in length, the gonodendra show a continual 

 increase in size, they grow especially in length (length of a gonodendron with its gonostyle 

 7 mm., breadth 2'/., mm.). 



E. Of E (length \- 38'/^ cm.) nothing particular is to be mentioned. The gonostyles 

 and gonodendra increase in size, some siphons have fallen off; the fourth siphon of E has 

 lost its gonodendron, the seventh both tentacle and gonodendron. The stem gets thinner, 

 more string-like. The space between E and F has a length of 49,5 cm. Although of 

 considerable length there are only 6 siphons left, the other being lost. The stem becomes 

 fragile, breaks off easily. It is in many places wound spirally. The same is also the case 

 not only in the tentacles but also in the gonostyles. Between two siphons there are 

 bunches of tentacles which were so tightly clustered, that we thought it better not to try 

 to loosen them. 



F. F has a length of 38 cm.; it does not differ from D and the intermediate part. The 

 stem broke in two, during preparation. The are six siphons, each bearing a tentacle (some 

 are broken off) and a gonodendron. These are beautifully shaped and probably very near 

 maturity as it .seems to us that some gonophores have become detached from the very first 

 gonostyle, as this latter seems to be incomplete. They increase in length, not in breadth; 

 the fourth is especially well-shaped. 



Between F and G 31,5 cm. are left open. The unusual thinness and fragility of the 

 stem diminishes. It gets more normally string-like, somewhat transparent, flattened and shows 

 less contorsions. There are three siphons left whicli show only their tentacle, and as no 

 gonodendron is left, we may assume that the most distal gonodendron (of which only part 

 was drawn on PI. XIX) situated on V was the oldest and that gradually all the gonophores 



