98 THE OCEANIC HYDROZOA. 



This, however, is not exactly the case. At least, if the place of attachment of the appendages 

 is decisive, and the opposite surface is to be regarded as the upper, the crest lies horizontally 

 and on one side, hardly more remote from the under than from the upper surface." 



With respect to tiie "keim-biindeln," Leuckart's account of their structure contains no 

 addition to that of Von Olfers, which is not to be wondered at, as only spirit specimens were 

 at his disposal. He states (p. 209): 



" So much is certain, that these vesicles (the ovate and club-shaped bodies of Fhjsalia — 

 medusoid bodies of other S)pJiono2jJiorida) are not sexual organs, but are more or less 

 developed individuals of a second generation, which arise ascxually by budding and are capable 

 of sexual propagation, wliilst the SipJionoplioridcn themselves remain constantly without sexes." 



As we shall see, Leuckart nearly, though not quite, divines the true nature of these 

 bodies in this passage. 



In the same year 1851, the lamented Johannes Milller, the great anatomist of Berlin, 

 published in his 'Arcliiv' a translation of a brief communication which I had addressed to him,^ 

 and which comprised among other matters a description and figures of the reproductive 

 organs of PJij/salia, based upon the observations and drawings which will be given in 

 the present work. 



The last memoir upon Fhysalia to which it is necessary I should advert, is that published 

 in the 'Annales des Sciences Naturelles,' for 1853, by M. Dc Quatrefagcs. 



The author justly corrects tiie statement of Leuckart which I have quoted above, 

 so far as to point out that, in the natural position of the animal, the crest is vertical, 

 while the appendages are lateral; and he describes extremely well and faithfully the singular 

 somersaults which the P/ii/scdia describes during life by raising up the pointed end of 

 its body, changing its centre of gravity and tumbling over ; but I must confess that I cannot 

 regard the fact of the performance of these manoeuvres as any proof that tlie Pfii/salice 

 are in the habit of tacking (virent de bord), or that it " dccele une volontc bien determinee 

 et comme reflechie" (p. 114). On the contrary, as I have over and over again watched 

 the operation going on with great vigour in a dead calm, I cannot but think that if the 

 Phi/salice really imagine they are tacking or wearing ship, they exhibit a remarkable absence 

 of reflective capacity. 



In discussing the functions of the pore, M. De Gluatrefages contributes the following 

 remarkable observation : 



" One of my Plii/salice, which had already served for many investigations, suddenly began 

 to collapse. The loss of the gaseous matter evidently took place through the pore in 

 question. The bladder collapsed completelj' and floated on the surface of the vessel, without 

 giving any other signs of life than obvious contractions when I irritated it. 



" I believed the animal was dead, and setting it down for such in my notes, resumed the 

 occupation with which I was then engaged. A quarter of an hour afterwards, at the most, 

 having chanced to cast a glance at my Plipalia, I was greatly surprised to see it distended 

 anew, although a little smaller than it was at first, and erecting its crest in the air at the surface 

 of the water, just as when it was first brought to me." 



^ 'Ueber die Sexual-organe der Diphydse und Physophorid:e.' Miiller's 'Archir,' 1851, p. 380, 

 taf. xvii. 



