160 LECTURE IX. 



moving medusiform individuals, is most clearly determined ; and the 

 phenomena ax'e most important and suggestive. No one who wit- 

 nesses these changes in the form of different individuals, representing 

 one and the same species, but must feel that, by prosecuting these re- 

 searches, we shall arrive nearer and nearer to the possibility of solving 

 those questions, the difficulty of which has been eluded by the gra- 

 tuitous hypothesis of the transmutation of species, and which may lie 

 at the bottom of the mystery of the progressive introduction of new 

 specific forms of animal life upon this planet. 



" The natural system of classification," says Cuvier, *' must be 

 based upon a consideration of the totality of the organisation, and a 

 comparison of such in difierent beings, directed by the principle of 

 the subordination of characters." Granted. But suppose that 

 organisation to materially change at different periods of the life of 

 the individual of one and the same species, and these periodical 

 characteristics to be propagable by parthenogenesis ; which of these 

 periods, it may be asked, is to be deemed to manifest the typical 

 form, or that in which the whole organisation is to be studied and 

 compared ? 



The philosophic botanist sees in the tree the same condition of 

 an aggregate of essentially distinct individuals as the philosophic 

 zoologist sees in the compound polype or the compound monad. No 

 anatomist could look upon the polype of the Bryozoon, with its rich 

 organisation and independent generative system, as a mere part or 

 organ of a compound individual whole. No microscopical anatomist 

 now regards the Volvox as any other than a spherical group of dis- 

 tinct and essentially independent monads. The polypes of the 

 Anthozoa and of the Hydrozoa manifest the two lower grades of or- 

 ganisation in their sub-province ; but are as essentially distinct 

 individuals, as the polype of the Lagenella. The gemmiparous , 

 leaf of the Bryophyllum is the vegetable equivalent of the animal 

 polype, and is equally a distinct individual plant ; and, according 

 to the present botanical philosophy, it is a more typical individual 

 than the leaf which has been metamorphosed into the stamen, the 

 pistil, or any other element of the flower. 



By this analogy and course of reasoning, therefore, the naturalist 

 would seem to adhere closest to Nature, and to interpret her best who 

 should classify his subjects according to the typical character pre- 

 sented by the individual, whatever might be the phase of its develop- 

 ment in reference to the genetic cycle ; and the zoophytologists are 

 justified on this principle who include the Campanularia and the 

 Coryne amongst the Hydrozoa, notwithstanding their medusiform 



