2 My. II. M. Bernard on the 



developmental feature is a repetition of some ancient con- 

 dition or a recent adaptation*. As I have already often 

 maintained, lines of pliylogenetic growth can only be satis- 

 factorily established by the discovery of connected series of 

 variations, morphologically and chronologically arranged. 

 The skeleton alone can supply us with such series, and that 

 of the corals probably with a more complete series of forms, 

 extending /rom the Palceozoic era to the present day, than will 

 ever be obtained of any other animal group. Whether, there- 

 fore, the skeleton be of great or of little importance in itself 

 in the morphology of the corals, it alone supplies us with 

 what we want' — a continuous series of homologous structures. 

 On this account alone, then, when our aim is taken into 

 account, we are obliged to confine our attention to the 

 skeleton. 



As a matter of fact, the skeleton is of paramount importance 

 in the coral organism. Tiiere is a sameness in all the soft 

 parts which limits their morphological importance in any 

 comparative study. Their chief variations may, for practical 

 purposes, be said to be repetitions of the variations of the 

 skeleton which they secrete. The skeleton is, par excellence, 

 the chief structural feature of the coral, its relation to the soft 

 parts being extremely simple. It is, as we now know, thanks 

 to the researches of von Koch, Heider, Fowler, Bourne, 

 Ortmann, and Miss Ogilvie, an excretion of the basal parts 

 of the outer wall of the body, and hence morphologically it is 

 external to the organism. At times very complicated, it is 

 an organ of protection and support for the body of the polyp, 

 or, in colony formation, for the colonies of polyps, the polyps 

 themseh^es, thus protected, having, as a rule, remained simple 

 and primitive. I'he corals, indeed, present us with a group 

 of organisms still primitive enough to illustrate the fact that, 

 of the earliest niorphological modifications of the living 

 matter, skeletal formations were the most pronounced. This 

 is strikingly exemplified by the Foraminifera and Kadiolaria, 

 in which there is a wealth of skeletal formations with little 

 or no visible variation of the soft matter. Again, in the 

 sponges the skeletal variations far outrun those of the soft 

 parts. The same is true of the stony corals. 



In what follows, therefore, I shall make no detailed refer- 

 ence to the soft parts or to the excellent work which is being- 

 done with their help by Dr. Duerden towards the elucidation 



* N. Guldberg and Nansen, " On the Development and Structure of 

 theAVhale," Bergens Museum, 1894, p. 39; also Sedgwick, Proc. Fourth 

 luternatinnal Congress of Zoology, 1898. p. 74. 



