1865.] Hincks on Zoophytes : the History of their Development, 405 



We must emphasize this fact. The small bud on the surface of 

 the Hydra's body, which discharges the office of ovary or spermary, is, 

 to all appearance, identical in composition and manner of growth with 

 the bud which is matured into a new individual, in its earliest stage. 

 The Hydra-bud and the sexual-bud start from the same point, and 

 travel together for a while on the same road ; but the latter is arrested 

 in its course, and adapted to a special function, while the former 

 reaches the goal of separate individual existence. In other Zoophytes 

 this reproductive bud makes a nearer approach to the Polypite form ; 

 and in the kinds which originate free Medusoids, it is even furnished 

 with a mouth of its own, to which prehensile appendages are often 

 attached, and a distinct nutritive system. It is, in fact, in such cases 

 a sexual Polypite, with accessory locomotive organs. Of the animal 

 plant, we may well call it the floating flower-bud. 



The Hydra is a free and solitary being, and of the simplest structure. 

 Its gemmae are cast off successively, and prolific as it may be, it is still 

 permanently single. But in other members of its tribe, the budding 

 process has a very different result, a result similar to that with which 

 we are so familiar in the plant. The gemmaa are retained in con- 

 nection with the original stock, which is itself fixed, and a compound 

 structure is formed, a commonwealth of Hydras, indissolubly united 

 like the leaf -buds of the tree, and partners in the same life. In these 

 composite Hydroids, a slight modification of the essential elements, 

 as found in the Hydra, produces a very important change in external 

 aspect. The outer membrane excretes a horny covering, that clothes 

 and protects, more or less completely, the soft portions, investing the 

 stems and branches of the arborescent kinds, and in some families 

 expanding into graceful calycles around the associated Hydras, into 

 which they can retreat for shelter. It is by this covering or polypary 

 that the Zoophytes are best known, for in our museums they are 

 commonly represented solely by the chitinous casts of their elegant 

 and exquisitely-ramified forms. 



The compound and plant-like growths, evolved by repeated bud- 

 dings from a single germ, are often of very considerable size, some 

 thousands of polypites being in some cases united in the one organism, 

 each of which is actively engaged in the capture of prey for the 

 nutrition of the commonwealth. The beauty of these vegetating 

 animals is surpassingly great. They take the form of exquisite 

 plumes, of miniature trees laden with polypites, like milk-white blos- 

 soms (which Marsigli took them to be), of clusters of tubes surmounted by 

 vividly-coloured heads, encircled by a double wreath of tentacles, and 

 looking like bright flowers on long and slender stems, of twisted 

 pedicles bearing crystal chalices aloft, in each of which a Hydra dis- 

 plays itself, and casts forth its embossed arms over the crenated 

 border, of a delicate netted stolon creeping over the surface of the 

 sea-weed, and sending up at intervals tiny campanulate cells, fit to be 

 the di'inking-cups of fairies. Great is the variety, and great the 

 beauty. But whatever may be the form or size of the Zoophyte, 

 whether its federation number tens or thousands, it has its origin in a 



