LECTURES ON EMBRYOLOGY. 



41 



rangular form. The outline of these bell shaped 

 bodies being, when seen from below, as in figures 

 A and B. The angles are prominent, and from 

 them there are colored specks rising, similar to the 

 eye specks of common Medusas. A membrane is 

 stretched across over the central cavity, leaving, j 

 however, an opening below ; and from the cor- 

 ners are produced short tentacles, which, in the ; 

 progress of time, grow longer and more moveable. 

 In the interior there is a sucker-like projection, 

 first with a single margin, which will be fringed 

 afterwards. From these details it is plain that 

 these buds, when fully developed, resemble most 

 remarkably the small Medusa, (Plate XXVIII, fig. 

 C) to which I have before referred. 



Indeed, they are finally freed from the stem 

 upon which they grow, and move as independent 

 animals. 



The structure of these small animals is indeed 

 very simple ; as they have only four straight tubes 

 branching in four directions from their summit. 

 The investigators of these phenomena have been 

 unwilling to refer them to the class of Medusae, 

 but have considered them as closely allied to Tu- 

 bularise, and belonging therefore to the class oj 

 Polypi. They have compared the Medusa-like 

 buds of Coryne, Syncoryneand Podocoryne, (Plate 

 XX,) to the crown of the Tubularias, (Plate 

 XXX, fig. A.) and you see that the comparison is 

 very close. You see that the hollow tube within 

 the Medusa-like bud (Plate XX, fig. A.) will com- 

 pare to the hollow cavity with fringes hanging be 

 low the tentacles of Tubularise. (Plate XXX, fig. 

 A.). Then you see the tentacles above spreading 

 around the bunches of eggs and arising from the 

 upper cavity, as the main cavity of the little Me- 

 dusa-like buds surrounds its inner hollow tube, 

 from which the eggs are developed in them, form- 

 ing also special bunches, exterior to the inferior 

 or anterior part of the alimentary canal, so that 

 the resemblances between these bell-shaped bulbs 

 (Plate XX, fig. F) and the crown of Tubularise 

 (Plate XXX, fig. A) is as close as it can be. The 

 conclusion derived by Steerstrup from these facts 

 is that the genera Syncoryne, Coryne and Podoco- 

 ryne, (Plate XX, figs. A, B, C) should no longer be 

 considered as genera by themselves, but only as 

 the nurses of animals of a higher order, the little 

 Medusa-like animal, but that they nevertheless 

 should remain with the Polypi near the Tubula- 

 rias. Steerstrup insists upon this point, when he 

 says : " The more perfect forms, however, notwith- 

 standing their resemblance to Medusae, must still 

 occupy the systematic place of the clariform Po- 

 lypes, or Coryne, as animals closely allied to Tubu- 

 larise, Sertularia, &c. &c. 



Let us now examine the Tubularias and also the 

 Campanularise, as they have been carefully studied, 

 and then we shall be prepared for an opinion upon 

 these conclusions. We have here [Plate XXVIII] 

 a stem of the Campanularise, which has branches 

 of various kinds. How these branches grow must 

 be examined more fully. 



[PLATE XXVIII CAMPANULARISE. j 



In a growing stem the first origin of the stem, 

 we shall examine afterwards there is in the inte- 

 rior a cavity, which cavity expands above and 

 forms a kind of stomach ; the moveable part of 

 the animal forming tentacles around, and the 

 mouth being therefore above. And from the side 

 of such a Polype there will be, after a certain time, 

 a bud, forming a simple sac, communicating with 

 the main cavity, and the changes which have pro- 

 duced the main stem will be repeated here so as to 

 give rise to another Polype of the same structure as 

 the terminal one, with a open communication with 

 its main cavity ; and after by repeated budding, 

 numerous branches, all alike, have been found as 

 they are figured in this diagram, [Plate XXVIIIj 

 Where you see seven buds all alike,some new buds 

 forming in the axis between the main stem and 

 the first buds. And these new buds differ from the 

 former, inasmuch as the bud will not terminate 

 with a new Polype,similar to those of the first buds, 

 but will remain closed, and while it is still closed 

 there may be buds arising on its side in which eggs 

 are developed. 



Loven, who described these phenomena more 

 extensively, represents these axilary buds as giv- 

 ing rise, bv budding, to new branches, remaining 

 longer shut in a common cavity, and indeed being 

 branches similar to the external one; with the 

 only differences that the terminating animais have 

 smaller tentacles, and are of a slightly different 

 shape; communicating with the main cavity, and 

 giving finally rise to free moving individuals ; 

 whilst there are below simpler sacs, of the same 

 order, but still less developed. Plate XXXV rep- 

 resents the various stages of this growth. 



Now these sacs are something like buds ; but 

 they are, in fact, eggs, which, In the beginning, 

 are simple buds, or diverticula from the common 

 cavity, so that we can consider the whole as buds, 

 which throw out new buds, from which eggs are 

 developed, in the shape of pouches. And that 

 these are eggs, can be proved by the characters 

 which distinguish eggs. (PI. XXXV. fig. D.) They 

 may have a germinative vesicle, and agerminative 

 dot ; and there a new animal is formed, which 

 will escape as soon as the upper buds, which are 

 now full grown, have removed the closing opercu- 

 lum : so that, by a process of budding of bud- 

 ding egg-like buds there is a new generation, 

 formed, which does not remain upon the primitive 

 stem, but is freed; and when freed, the germs 

 arising from the eggs are elongated, and little 

 cylindrical animals, which swim free, appear; and 



