ORGANIC DEVELOPEMENT. 89 



spires are extremely short, great concentration being required for the 

 new developements which are to take place. The spiral arrange- 

 ment, observed in the vegetable kingdom, has not been detected in 

 the tentacles of an Actinia. Yet as this arrangement is due merely 

 to developements taking place successively from the different sides or 

 reproductive points of an individual, in regular order, it is altogether 

 probable that something similar to it may yet be made out. Repro- 

 duction is an exhausting process, and on this account it does not take 

 place twice successively from the same side.* 



In the developement of polyps in the Oculina, a spiral arrangement 

 is apparent (^ 67); but, as the number of budding points in these 

 polyps is twenty-four, and only five in very many plants, as great a 

 regularity cannot be expected in the former as in the latter ; for the 

 intervals between the budding points are so small, that slight causes, 

 es25ecially a freer exposure to the external waters from being less 

 crowded by the polyps in one part than another, will affect the posi- 

 tion of the point from which the next bud proceeds.f 



* Since this work was put to press, the author has found that Agassiz describes the 

 plates of the Echini, as developed in a .spiral order. See Agassiz on the Echinoderrnata. 



t From the above analogies, it would seem that the gemmating individuals in plants, 

 as well as the oviparous, consist of several leaves combined, and, therefore, that we can- 

 not properly speak of each leaf as a complete individual in itself. Yet the conclusions 

 we would deduce, follow equally well whichever view be adopted. A few other analogies 

 between the plant and zoophyte may be noticed here, on account of their bearing upon 

 the point just discussed. 



The developement of flowers exhausts the energies of a plant, sometimes so far as 

 to lead to immediate decline and death. There is a species of palm, which flowers, and 

 soon after dies." The Century Plant is another remarkable example.'' Have we not an 

 analogous fact in the strange mode of reproduction in certain CyathophyllidEB, represented 

 in the figures, to § 81 ? The parent, in this case, surrenders its existence soon after the 

 developement of a young bud, which, when completed, actually stands upon the dead 

 remains of its progenitor, preparing to make the same self-sacrifice. A still more per- 

 fect analogy to this process is found in the growth of the Colchicum and some allied 

 plants, in which the root of one year dies as it developes the bud of the next. And the 

 general process of growing and dying, in corresponding progress {§ 62), has frequent 

 illustrations in the vegetable kingdom ; for instances of which, we may refer to the 

 Botanical Text-book, by Dr. A. Gray,'^ or other Treatises on Vegetable Physiology. In 



' The Corypha or Talipot tree. Gray's Botanical Text-book, 2d edit., New York, 1845, p. 165. 



i" Ibid., p. 168. 



' See Botanical Text-book, p. 63, ^ 86. " The Solomon's Seal and Diphylleia offer simple illustrations. 

 They make an annual growth by the developement of a bud, wliich, rising into the air, forms tlie flower- 

 ing stalk of the season; this falls away in autumn, leaving a broad scar, and meanwhile a new bud is 



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