LECTURES ON EMBRYOLOGY, 



ing from the sides of the stomach, being, indeed, 

 simple pouches from the stomach. I ought to 

 have mentioned before, that the eggs in Medusae 

 are universally formed in connection with the ali- 

 mentary tube, and that in some of them, as the 

 small species of Boston harbor above described, 

 they are simply diverticula of the digesiive cavity, 

 formed in coecal appendages of the same, to be- 

 come free, independent eggs afterwards. , Their 

 position varies even most remarkably along the 

 alimentary tubes, in some, that before mentioned, 

 being developed along the central proboscis ; in 

 others, the Stomobrachium, being formed in four 

 bunches along the four tubes diverging from the 

 central cavity. Their mode of formation in such 

 positions has nothing more to astonish us, since 

 we know, from the investigations of Sars, that 

 there are Medusas, the Cythers, in which new indi 

 viduals are developed from buds arising from tLe 

 stomach. At a certain epoch the whole genera- 

 tion produced, arises by transverse division of the 

 stem derived from the eggs of the Medusae, pro- 

 ducing a number of connected individuals, from 

 the sides of the primitive stem (Plate XIX. Fig. H) ; 

 there are also often found buds growing upon the 

 lower portion, but invariably, at some period, the 

 perfect Mudusge will produce eggs. 



In some Polypi we have also eggs arising from 

 the sides, like buds as in Hydra. [PI. XXIX.J We 

 have here, [Plate XX] from Polyp, Syncoryna and 

 Podocoryna buds arising which differ entirely from 

 the main stock, but which are successively freed 

 from it, and which give rise to animals which are 

 metamorphosed into real Medusae. Instead of be 

 ing considered as Polypi, those beings should no 

 longer.be considered as perfect animals should 

 no longer be arranged in our systems by them- 

 selves, any more than Ephyra, the larva of Medu 

 S83 [Plate XIX fig. J.J; any more than Strobila [Fig. 

 I.J or Scyphistoma [Fig. E.]. They are only to 

 be considered as the stages of growth of Medusae ; 

 in some of which the regular Polyp divides into 

 many buds, forming as many Medusae [Plate XX 

 fig. B ], or in others, of which simple Polypi give 

 also rise by budding to regular Medusae, there being 

 simultaneously other modifications of the process- 

 es of budding introduced, by which the animal is 

 finally brought to its higher metamorphosis, [Fig. 

 A.J; the budding being [Plate XX fig. B.] the step 

 by which the higher metamorphosis is introduced. 

 The free individuals , which differ so much from 

 the parent stock, being finally cast off. 



In Medusse proper the budding does not intro 

 duce the higher metamorphosis; this taking place 

 only in the individuals formed by transverse divi 

 sion. 



Now, let us for a moment compare such a being 

 as Agalmopsis (Plate XXVI) with the dividing 

 stock of Strobila (Plate XIX, fig. I). We see at 

 once that their position is inverted. Here (Plate 

 XXVI) the fringes hang downwards, but here 

 (Plate XIX, fig. I) they are upright. To institute 



a close comparison, we must therefore consider 

 them in the same position, and the resemblance 

 will be striking, especially towards the narrow end. 

 But when we know that in Polypi buds of various 

 aspects can arise from one stem, and remain con- 

 nected with the cavity of the main stem, as it is 

 here shown in Campanularia (Plate XXVIII) the 

 connecting axis being the main body with a con- 

 tinuous cavity which extends into the branches 

 we have no reason to wonder at a similar growth 

 in animals like Strobila (Plate XIX, figs. G and H) 

 where there is also a similar connection between 

 the bud and the main cavity of the body. 



And now in Agalmopsis (Plate XXVI) instead 

 of considering those various appendages as organs 

 of a simple animal, let us for a moment inquire if 

 we could not consider them as buds of various 

 kinds remaining around one stock, and forming a 

 community of heterogeneous individuals, living a 

 common life, in the same manner as in polypi, 

 where we have observed individuals, though some- 

 what heterogeneous, living also a common life. 

 And if this comparison can be carried out, we 

 have established that Agalmopsis must be consid- 

 ered as a community of distinct individuals. 



Now, what are, in the first place, those largest 

 bottle-shaped appendages ? They are considered 

 as suckers. But they ajre suckers which pump 

 food, which digest it in each of these bottles. 

 There is a cavity in which the food is digested; 

 and the result of this digestion is circulated 

 through the main tube. It is a condition identical 

 with the condition of the polypi, in which a new 

 bud arises to remain connected with the main bo- 

 dy, to have, however, a cavity of its own in which 

 to digest food, and then circulate it with the main 

 mass. Here (Plate XXVI) is another kind of 

 suckers, but performing the same function. They 

 are similar individuals in a lo-ver degree of 

 growth. 



At first these bottle-shaped open suckers are small, 

 simple appendages from the main tube,which grow 

 larger and finally assume a more individualist life, 

 so that we would have eating individuals upon a 

 common stem, which provide the whole communi- 

 ty with food. They are the mouths, the eating in- 

 dividuals other appendages which seize upon 

 the prey and which bring it to the suckers, may be 

 considered as compound stems. Of these apporates 

 here is one highly magnified : you have first, the 

 bottle-shaped apporates with their various modifi- 

 cations. Here we have the nettling organs, which 

 are,when highly magnified, also bottle-shaped, and 

 from which threads hang down. They are another 

 kind of individuals, suspended by their peduncles 

 and from which fringes hang down ^but not sim- 

 ple individuals. They are individuals which bud 

 in their turn, so as to form groups of individuals 

 groups of catching individuals. 



Then there are other buds, which remain hollow 

 cavities, and are considered as vesicles to suspend 

 the animals. It is the swimming apparatus of the 



