174 Revieics — Miss Maria Ogilvie, B.Sc. — 



that the structure of the calicle wall, or even that the minute 

 structure of the septa, will supply us with the means of discovering 

 the evolutionary history of the stony corals. But, in the meantime, 

 I frankly confess that I do not personally regard these sets of 

 differences now under discussion as of the very first importance, 

 inasmuch as, in many cases, they can be shown to be secondary, and 

 dependent upon the life of the secreting organism. I accordingly, 

 perhaps perversely, agree with the older observers who ranked 

 first and foremost features most intimately associated with habit 

 of life. It seems to me that differences in structure and texture 

 gain their real importance only as they reveal to us differences of 

 habit. It is thus not a question of rejection of characters, but 

 merely of selection for first, second, and third place. I can perhaps 

 make my meaning clearer by coming once more to close quarters 

 with the work we are discussing. On page 329 Miss Ogilvie says : 

 — " My own opinion is that the most intelligent way of studying 

 corals is not to approach them by means of any fixed system of 

 subdivisions, but by some such way as I have tried in drawing 

 up the phylogenetic scheme below, where the worker first studies 

 the anatomy of the soft parts and the structure (microscopic) of the 

 skeleton in one common type [sic] of each of the living families of 

 corals. According to my classification there are ten of these." 

 This is very good as far as it goes, but the fundamental error in 

 it is that it supplies a miserably insufficient basis on which to build 

 np a natural system. A few, i.e. ten, of the more striking variations 

 in coral structure is all that can possibly be obtained by this 

 method. Miss Ogilvie would be the last to admit that the countless 

 transition forms revealing the lines along which these variations 

 have travelled, are to be left entirely to the fertile bi'ain of the 

 individual, or even to be gained by a cursory oversight of a few 

 intermediate specimens gathered at random here and there. 

 Further, Miss Ogilvie's chief types are in reality selected in the 

 first instance at random. What can be said for such a principle 

 of selection as the following? (p. 326) : "Besides, I hold that, as 

 the Poritid^ are reef-builders, on the grandest scale known in the 

 Madreporaria, it is the reef-type which should be taken as the 

 standard for the family, and not the small astrgeiform colonies 

 formed by some species." And why is Turhinaria mesenterina 

 chosen as specially typical of the genus : may it not be an extreme 

 form ? 



But this is not peculiarly Miss Ogilvie's method. The tendency 

 to exaggerate the morphological value of the one or two isolated 

 types studied is almost universal. For instance, the detailed study 

 of the development of a single mite has recently been made the 

 basis for a lengthy discussion on the phylogeny of the whole class 

 Arachnida. 



Indispensable as is a thorough knowledge of types of calicle 

 structure, I repeat that it is not enough to build a phylogeny upon. 

 These types are not fixtures ; they are only stages in the evolutionary 

 processes, and the only philosophical method of dealing with them 



