412 Original Articles. [July, 



and the exquisite delicacy of its tissues may well remind us of the 

 flower of the plant, with its painted petals, and campanulate corolla, 

 and central mass of colour ; and if the flower-bud were in any case set 

 free to float in the air, and there distribute the seeds matured in its 

 ovary, it would be the exact analogue of the locomotive bud of the 

 zoophyte. 



A study of the earlier stages in the development of this body will 

 confirm the view which we have given of its nature. It is at first 

 an outgrowth of the body-wall, an extension of the two membranes, 

 including a small sac-like cavity, ft is identical with a Hydra-bud. 

 The outer layer, as we have seen in the case of Clava, divides, and 

 an external covering is formed, within which the development of the 

 bud proceeds (Plate i. fig. 3Z>). We shall not follow in detail the 

 changes which supervene, but merely state generally, that the same 

 layer is again split into two, and that the bud instead of continuing 

 simple, and maturing and discharging its products in situ, is invested 

 by the membranous envelope thus formed, which becomes the 

 swimming-bell in time, and at length bears it from the stock. When 

 the bud has reached a certain point of development, its outer en- 

 veloping sac is ruptured, and it bursts, as it were, into flower; the 

 Gono-zooid now nearly perfect, and ready for freedom, hangs on its 

 slender pedicle (Plate i. fig 3a), until by the vigorous contractions 

 of the disc the frail bond is severed and it floats away. 



To complete this portion of our subject, it is only needful to pass 

 in rapid review some of the intermediate forms or conditions of the 

 reproductive zooid, which connect the two extremities of the develop- 

 mental scale. 



(1.) It sometimes takes on the contractile swimming-bell, and to 

 all appearance is on the usual road to separate existence, but is ar- 

 rested before reaching the goal, and remains a fixed Medusiform bud. 

 The central peduncle behaves like any simple reproductive sac, and 

 discharges its products, where it is. In such cases the tentacles are 

 rudimentary, and the mouth also, if present at all.* 



(2.) A somewhat lower stage is met with in the common Tubularia 

 indivisa of our coasts. In this zoophyte the sexual bud (Plate ii. fig. 4) 

 is permanently attached, but it is furnished with the umbrella (b) 

 in which the canals are present, and the orifice, with four tubercles, 

 representing the four marginal tentacles. The generative sac (c) 

 destitute of a mouth occupies the centre. There is every preparation 

 for free existence up to a certain point, but the bud remains to the 

 end packed up in the outer sac (a) and the swimming-bell is converted 

 into a chamber or nursery, in which the embryo (d) completes its 

 development, escaping at last through the orifice above. 



(3.) In the remarkable Campanularian Zoophyte the Gonothyrcea 

 Loveni, Allman (Plate ii. fig. 8), we have another modification of the 



* Loven first described this form in Lis famous paper, entitled ' Bidrag till 

 kannedomen af Sl'agtena Campauularia ocli Syncoryna,' published iu 1S36 ; and he 

 speaks of the peduncle in his Syncoryua ramosa, as possessing " an exceedingly small 

 mouth," — "en ganska liten munn omgifven af omkring tio smd tuberkler — rwlimenter 

 till munntentahler." 



