3S4 DISCOVERY REPORTS 



There appears to be no recent summing-up of our knowledge of the homology and functional 

 morphology of palpons and it will not be out of place to consider the subject briefly here. We have to 

 go back to HaeckePs great ' Challenger ' report (1888) to find anything of the sort. Haeckel set great 

 store on allowing the empirical and speculative methods of research to converge. Nevertheless, while 

 I am a sincere admirer of his prodigious pioneering work, I always regret that Haeckel allowed so 

 much hypothetical interpretation and terminology to colour his observational records, because a great 

 deal of it now seems to be quite mistaken. It is a pity also that he should have idealized his finished 

 figures in order to make his preliminary sketches complete and attractive. But these are trivial 

 criticisms of his painstaking work in general. 



What he has to say about palpons is contained in four sections of his general introduction, under the 

 headings: (1) palpons or 'tasters', (2) cystons or anal vesicles, (3) palpacles or ' tasting ' filaments (the 

 German word 'tasten' meaning to touch) and (4) gonostyles or reproductive stalks. Haeckel, while 

 agreeing that palpacles were only the tentacles of palpons and not a separate sort of bud, contrasted 

 palpons with cystons, saying that palpons were mouthless and had no glandular villi, whereas cystons 

 could empty fluid and excretions from the canal system through a terminal opening which was to be 

 regarded as an anus. He used Allman's term 'gonostyles' or ' blastostyles ' for what he called the 

 'sexual palpons', frequently branched, whose sole function was to produce gonophores. A subsidiary 

 title for his section 4 is 'Blastostyles, Gonoblastidia, Gonodendra, Klinozooids '. The term gono- 

 dendra he specifically applied to large clustered masses of gonophores attached to branched gono- 

 styles, which last he regarded as secondary polypoid individuals. He mentioned that palpons are 

 found generally distributed in the physonects and cystonects, but not in the calycophores. 



As a result of my own observations on living and preserved material of physonects and cystonects, 

 I conclude that there is no real distinction between palpons and cystons. Terminal openings may 

 suddenly appear where there has been no previous indication that such a thing is possible. I cannot 

 now find my field notes on the subject, but I think that it was in Nanomia bijuga that I first observed 

 (at Villefranche) the flattening-out of palpons in a progressive peristalsis followed by an opening-wide 

 of the tip of the palpon and the ejection of particles. In some species of Forskalia, for example, the 

 Mediterranean species with the lemon-coloured spot on the velum that I call edwardsi, I have often 

 observed the well-known ejection of an orange-coloured liquid from the tip of a palpon. I have 

 observed palpons opening in other species too. In one particular preserved specimen of Physalia 

 phy salis many of the palpons were fixed in the act of opening (PL XXV, figs. 2, 3) and in others there is a 

 collection of dark matter, usually distributed over the villi, near the tip as if about to be ejected. It 

 appears to me that the palpons are to be regarded primarily as reduced secondary polyps budded from 

 the bases of replicated gonozooids. Secondarily, they may become separated from the gonophores 

 and gonodendra. This can be very clearly seen in a small specimen of Athorybia rosacea, taken by 

 'Discovery II' in September 1955, off Lanzarote at St. 3308, and brought to me by Dr Kramp. It 

 can also be clearly seen in Forskalia edwardsi, and I have illustrated it in a figure of Marrus antarcticus 

 (Totton, 1954, fig. 21). In Physophora hydrostatica, where the palpons are very large, this relationship 

 is not apparent in mature specimens, which represent the condition found in the post-larva developed 

 to a higher degree. In the physonect Nanomia bijuga a bunch of male and a bunch of female 

 gonophores is budded from the pedicel of each palpon. I think it probable that some palpons 

 have come to act as food-reservoirs for the growing gonodendra — in Pyrostephos antarcticus they 

 are usually full of liquid fat or oil — as well as organs of defaecation. In Physophora, Forskalia and 

 Athorybia they are particularly active sensory organs. In Apolemia uvaria there is a kind of palpon, 

 few in number, that is brown and heavily armed with nematocysts. The palpons of Physalia physalis 

 have a beautiful pad of nematocysts on one side of the tip and on the tip itself. In this species all 



