416 Original Articles. [July? 



We have thus passed in review the various elements of the Hy- 

 droid life-series, and endeavoured to supply their interpretation, and 

 to exhibit their mutual relations. We have traced the sexual bud from 

 its simplest to its most complex form, distinguished between its essen- 

 tial and accessory parts, and shown that it is in all cases a polypite 

 structure modified for the special reproductive office. We have col- 

 lated the nutritive and sexual zooids, and shown that even the so- 

 called Medusa, unlike as it looks, is structurally identical with the 

 polypite, the elements of which are adapted in it to subserve a different 

 function. And we have sought and found a key to many of the most 

 remarkable passages of the history in the analogies of the vegetable 

 world. 



And if some of the marvel has seemed to vanish as we have pro- 

 ceeded, we venture to think that the real romance of Nature is more 

 than an equivalent for the loss. 



There must always be a certain fascination in a history which tells 

 us of animals composed of multitudes of individuals (zooids) living 

 an associated life, and so combining as to produce the most graceful, 

 plant-like structures, vegetating like a tree, putting forth thousands of 

 polypites like leaves, each a provider for the commonwealth, — putting 

 forth also a company of buds charged with the perpetuation of the 

 species, ripening in transparent urns, and scattering their winged seeds 

 broadcast, or sent forth, moulded and painted by the highest art, like 

 fairy emigrant ships, freighted with young life, to colonize distant 

 seas. And these are the simple facts of Nature. 



We have often had occasion in the course of this article to refer to 

 Professor Allman's labours in this department of Natural History, and 

 to the important contributions which he has made to our knowledge 

 of the Hydroida. These it would be impossible to over-estimate. At 

 the same time, we confess that some of the views propounded by our 

 distinguished friend fail to satisfy us. 



His classification of the Gono-zooids under two divisions, to which 

 he has given Greek names, which we omit, lest the general reader 

 should forswear our favourite science on the spot, appears to us unne- 

 cessary, if it be not misleading. The various modifications of the re- 

 productive system pass one into another almost insensibly, and any 

 line drawn to bisect the series must be purely arbitrary. To separate 

 the more distinctly Medusan forms (so called) from the simpler is to 

 run the risk of creating a false impression as to the relations between 



history ; but to all appearance a polypite was in course of development. An 

 account of these observations was presented to the Nat. Hist. Section of the Brit. 

 Assoc, at the meeting for 1864. 



Since the passage in the text was written we have seen a paper by Prof. 

 Allman in the June No. of the Annals of N. H., in which he describes " the retro- 

 grade metamorphosis of the Medusa into the polypite," in the case of a new 

 Syncoryne, which he has discovered in Scotland. Curiously enough the Gono-zooid 

 of this species seems to be almost, if not absolutely, identical with that of the 

 Coryne eximia, in which we had previously observed the same change, and which, 

 in its turn, we have shown to be identical with that of the Stauridium productum. 

 These facts would lead us to a very interesting chapter of the history, upon which, 

 however, we have not space to enter at present. 



