6 DISCOVERY REPORTS 



MORPHOLOGY OF PHYSALIA 

 Historical 

 So much has been written about Physalia that useful observations are likely to be overlooked. Many 

 of the accounts are travellers' tales which have been shown to have no foundation. It would take too 

 long and be too unprofitable to make a new summary, especially as five previous ones exist, namely 

 those of Lesson(i843),Quatrefages(i8s4), Huxley (i8s9),Haeckel(i888),and Chun (18976). Lesson, 

 who had frequent opportunities to make observations on Physalia during the long voyage of ' Coquille ' 

 (1822/5) published an account of them in 1827 and 1838, and repeated these more fully with a survey 

 of past observations in 1843. 



I have come across no satisfactorily complete account of Physalia's complicated morphology. 

 Chun (1887) did once promise to deal with it thoroughly in a monograph on the Siphonophora but the 

 work never materialized. Olfers (1832) gave a useful list of early references and names and figured the 

 gonodendra. He mistook discharged nematocysts for Vorticellids attached to the tentacles. Olfers was 

 of course writing before Wagner (1835) had published the first figures of nematocysts.* Trembley 

 (1744) has figured what were probably the undischarged nematoblasts of Hydra, but it was Sir Joseph 

 Banks's observations on Physalia, contained in his journal in an entry dated 12 April 1770 and 

 seemingly entirely overlooked by Weill (1934), author of the first monograph on the subject, which 

 provide our first knowledge of any nematocysts. I have to thank Dr A. M. Lysaght for drawing my 

 attention to this entry : ' . . . if touched by any substance they immediately exsert millions of exceedingly 

 fine white threads about a line in length which pierce the skin and adhere to it giving very acute 

 pain[.] When the animal exserts them out of any of the little knobbs or beads which are not in contact 

 with some substance into which they can pierce they appear very visibly to the naked eye like small 

 fibres of snow-white cotton.' Hooker published a shortened, rather dull and unscholarly version of 

 Banks's Journal in 1896.! 



On both 11 and 12 April, Banks noted that he had seen undoubted proof that the Albatross eat 

 Physalia: 'April nth. . . .an Albatross that I had shot dischar[ge]d a large quantity[,] incredible as it 

 may appear that any animal should feed upon this blubber whose stings innumerable give a much 

 more acute pain to a hand which touches them than nettles.' 



Banks also observed the 'kind of sail which he erects or depresses at pleasure'. But his other notes 

 on trimming the sail and being able to sail 'in any direction he pleases' are not so trustworthy. The 

 description of making it ' concave on one side and convex on the other varying the concavity or the 

 convexity to which ever side he pleases for the convenience of catching the wind ' is more likely a 

 description of righting behaviour. 



In the British Museum (Natural History) is a specimen, still well-preserved in alcohol, which must 

 be one of Banks's (B.M. Reg. no. 1925.8. 13.2). The label on the old ' surgeon's round' bears the names 

 Holothuria physalis in much-faded ink. Its style, with a ruled line at top and bottom, and the hand- 

 writing corresponds well with that of labels on three bottles of fishes, Serranus atricaadatus, Anthias 

 sacer and Sebastes kuhlii, all known I am told to be Banksian specimens. The Banksian Physalia has a 

 float measuring about 7 cm. in length. It bears seven major tentacles and a number of gonodendra 



* Wagner mistook the discharged nematocysts from the acontial threads of Actinia holsatica from Heligoland for sperms. 

 Soon afterwards Ehrenberg (1838) published a large coloured plate of Hydra vulgaris, showing a number of irregularly dis- 

 charged stenoteles, all with the tip of the thread still within the nematoblast, and the capsule at the outer end. He was under 

 the impression that the capsules could be shot out and withdrawn again. 



f The original is now in the Mitchell Library, New South Wales. A complete edition is to be published shortly under the 

 editorship of J. C. Beaglehole. 



