2 LUCERNARI^ AND THEIR ALLIES. 



latter be monomerous (as in Hybocodon and Corymorpha producing free medusa;), 

 or polyinerous (as in Coryne witli free medusa;). 



3.' The possibility of a third category of individuality had not arisen in the 

 minds of philosophic naturalists until the question of the bilaterality of the two 

 lower grand divisions of the animal kingdom had been discussed so vigorously, 

 and elevated to such a prominence among the theories of the day as to extend its 

 influence even to the determination of the oneness or duality of the members of 

 the highest of all grand divisions, and indeed the highest of all animals, man 

 himself Here, at this point, we find breaking in upon us the Teratological essays 

 of St. Hilaire, and the more recent decisions of Wyman upon the same subject, 

 with the strange confirmations of Lcreboullet, by his discoveries of the fissigem- 

 mation of the piscine egg, and the evolution of two heads or two tails from one 

 centre of development — the dtialistic tendency of the highest vertebrate empha- 

 sized by the presentation of the living tangible reality.^ 



4. Such possibilities among the Vertebrata staring us in the face could not but 

 send the thoughts flashing back among the inferior, less determined, less dift'eren- 

 tiated organizations; and the mind's eye nfeeded not to dwell long among the 

 many-headed Vorticellae, Polypi, Hydromedusae, Bryozoa, Ascididse, Pyrosomidae, 

 Salpse, etc., before discovering a multitude of more than shadowy tendencies ; 

 it became fixed upon numerous sharply and clearly established, unmistakable 

 dualities and pluralities ; all arising from one common centre, the ovum. Had we 

 not the problem of plural individuality solved here — a pohjcephalism — ? the diffuse 

 vitality of the animal-egg of the lowest ranks of life outspoken in the indetermined 

 nuinber and localization of the subdivisions of the Polyp or Hydromedusa corpo- 

 ration • and even the organization itself undecided' as to whether it should 

 exemplify its oneness in a simple unit of form, as in the pseiidoincllvichhim^ of 

 Bryozoa, Ascidiadfp, or resolve its offices and configuration into the repetitive, mul- 

 tiplied sameness of the sexless and sexual proles of Salprc, Taeniae, Annelida;, and 

 Hydromedusa;, or the excessive repetitions of the genitalia of Polypi. 



5. The old type of monomerism, the vertebrate individual par excellence, has 

 then become the modern, more than transcendental duality. The originals of 

 multitudes of figures in St. Hilaire's " Teratologic," of the memoir of Lereboullet, 

 and of the condensed aphoristic sketches of Wyman stand forth the real, material 

 embodiments of the idea upon which all sentient life is founded. BUateralihj 

 does not express the thought, it embraces too little; it is to be classed with antero- 

 posteriority and dorso-ventrality, to signify the subdominant features of the animal 

 architecture ; features which evolve themselves as the concomitant resultants of 

 the development of the primitive dominant which originally gave shape to the 

 hipolar ovum. The embryologist, and to his thoughts the subject is most germane, 

 reflectmg upon the physical aspect of the forming egg, would naturally arrange its 

 features m two antagonistic fields; and thereupon attempting to define their 

 position m regard to the contour of the concrete sphere, almost inevitably would 



' See remarks of the author on this subject ia " Miud in Nature," utsup., p. 1. 

 See paragraphs 22 and 23. 



