EARLY RESEARCHES 9 



Physalia," ^ the Portuguese man-of-war, a colonial jelly- 

 fish (Proc. Linn. See, 1849), and the other "On the 

 Anatomy and the Affinities of the Family of the Medusae " 

 (Phil. Trans. Roy. Soc, 1849, Part 2, p. 413. Sci. Mem., 

 i, IV, p. 9^. Several other memoirs ^ may be grouped 

 with these, as well as the classical monograph on " The 

 Oceanic Hydrozoa" (Ray Society, 1858), of which 

 the publication was long delayed, owing to the penuri- 

 ousness of the Government. 



These publications deal with those lower organisms 

 known to the older naturalists as " Zoophytes," and now 

 technically named Ccelentera. They include hydroid 

 zoophytes, medusae or jelly-fishes, sea-anemones, corals, 

 and various other forms. Until Huxley's time the 

 systematics of this vast assemblage of apparently diverse 

 types was in a state of the utmost chaos, the attention 

 of previous workers having been chiefly devoted to 

 description and naming of species without due compari- 

 son. The young navy surgeon reduced this chaos to 

 order, and proved that a common plan of structure 

 dominates the entire series. He demonstrated, in short, 

 that the body of any one of these animals essentially 

 consists of two cellular membranes, bounding variously 

 shaped cavities, and suggested the equivalence of the 

 said membranes to "the two primary germinal leaf- 

 lets in the vertebrate embryo " (Prof. G. J. Allman, Life, 

 i, p. 40). 



' Brief notice only. The complete "Memoir on Physalia," op. cit., ii, 

 1855, pp. 3-5. Sci. Mem., i, xxxvi, p. 361. 



' " On the Anatomy of Diphyes, and on the Unity of Composition of the 

 Diphyidse and Physophoridae, etc." (Brief notice in Proc. Linn. Soc., 



1849. Complete Memoir, op. cit., ii, 1855, pp. 67-9. Sci. Mem., i, 

 xxxvn, p. 363). 



"Notes on Medusae and Polypes" (Annals and Mag. Nat. Hist., vl, 



1850. Sci. Mem., i, v, p. 33). 



"Ueber die Sexualorgane der Diphyidae und Physophoridae'' (Miiller's 

 Archiv., 1851. Sci. Mem., i, xiv, p. izz). 



