62 D1SC0PH0R.E. Part lU. 



and form a single structure, just witliiu the outer wall, and immediately without 

 the inner wall, thus forming a quasi third, or middle wall to the tentacles. Lest 

 it may be doubted that these fibres are contractile within the digestive cavity and 

 chymiferous canals, I would state, that upon being touched with a needle, when 

 they are laid open by a section, a distinct contraction and a wrinkling of the wall 

 of the canal may be observed. 



" The great contractility of the digitate bodies of the reproductive organs is 

 well known and undisputed, and j'et the muscvdar layer of these appendages is 

 directly continuous with that which underlies the wall of the digestive cavity and 

 chymiferous tubes, and, moreover, with the wall, embraces a solid core or axis, which 

 is a direct prolongation of the gelatinous layer, the same layer Avhich constitutes 

 the greater bulk of the body, and gives it a certain degree of rigidity. 



" In young specimens, two and a half inches in diameter", within the I'egion where 

 the fibrillar are concentric in the adult, the inner side of the cells of the outer 

 wall have their granular contents arranged in parallel lines, which form concentric 

 circles about the disk. The cells are fusiform and their longer axes trend par- 

 allel to the granular lines. At a little later period, the interior half of each cell 

 gradually divides off, after the manner of self-division of cells, and then the mus- 

 cular portion of each cell constitutes a layer hardly distinct from the cell itself, 

 and is more like a filamentous prolongation of the parietes of the same, than a 

 truly separate stratum. We may see the tendency to these prolongations in the 

 branching cells which are imbedded in the gelatinous layei*, not only of the actiual, 

 but also of the abactinal side, where they connect more or less with those in the 

 muscular layer; and in the digitate bodies appended to the reproductive oi-gans, the 

 branching, scattered cells, so characteristic of the gelatinous layer of the disk, are 

 very rare, and are imbedded in the solid, fibrous, muscular layei', which constitutes 

 the whole core of each appendage." 



There is another stage in the existence of our Aurelia, which deserves to be 

 noticed. After the spawning period, a large number of them, reduced in their 

 natural strength, and unable to resist the influence of the approaching stormy season 

 in the autumn, are cast upon the shore, while even at that time, large numbers 

 may be seen still floating upon the water, near its surface, in a more or less 

 dilapidated condition, though still alive. ' At this time they have lost, to a great 

 degree, their transparency, owing to the thickening of their tissue by an increased 

 deposition of animal substance. Their disk has become tough and almost leathery, 

 and is more elastic, though at the same time more brittle than it was before. The 

 tentacles are, for the most part, gone, as well as the eyes ; and this decomposition 

 of the margin extends so far, that even the marginal tube and parts of the anasto- 

 moses of the radiating tubes disappear. Yet even ' in that condition, the fluid 



