1897] SOME NEW BOOKS 127 



the septa and the coenenchyme. For her the form and structure of 

 the calcareous laminae or bars are the result of foldings, wrinklings, 

 and tuckings in and over of the flexible zooid. On p. 315 there is an 

 imaginative' description of the evolution of the madreporarian zooid, 

 which is represented as pulling in and tucking up its body in various 

 places, forming invaginations here, evaginations there, as if guided by 

 some predetermined impulse, and we are to believe that the form of 

 i he corallum is determined by these almost purposive wrinklings and 

 corrugations of the zooid, which fills up the cavities and folds of the 

 creases in its body with calcareous tissue. Eeferences, scattered 

 throughout the volume, to invaginations — a word, by the way, 

 which is used in a most puzzling variety of meanings with regard 

 to spatial relations — show that Miss Ogilvie is dominated by the 

 idea that the wrinkling and pitting of the soft tissues was the 

 antecedent, the formation of calcareous structures the consequent. 

 The skeleton, it is true, is formed by the soft tissues, but it by no 

 means follows that the form of the skeletal parts is the result of the 

 pre-existing form of the soft parts. The two elements have been 

 formed pari passu, changes in the one reacting upon the other, and 

 the final shape and mutual relations are the result of a continuous 

 correlated development of which w r e cannot affirm, at any given 

 point, that the growth of the one part preceded or dominated the 

 growth of the other. On Miss Ogilvie's supposition it is most 

 difficult to account for the formation of the canal s}'stem in perforate 

 corals, and we cannot but suspect that this difficulty has led to her 

 giving a theoretical rather than an actual picture of the structure of 

 Turbinaria and of Fungia. Not that Fungia is a perforate coral. 



In classifying the Fungidae, Miss Ogilvie has left out of con- 

 sideration the fact that the young Fungia is a true aporose coral, 

 indistinguishable from a Turbinolid, even to the absence or at least 

 the very slight development of synapticula. This fact points to a 

 close relationship between the Fungidae and the Turbinolidae, yet 

 they are classed far apart, the former among the Pollaplophracta 

 Septocorallia, the latter among the Haplophracta Murocorallia. In 

 fact, the more one examines the grounds of the classification adopted 

 in this work the less satisfactory does it appear. The group 

 Coenenchymata strikes one as purely artificial. The subsections 

 Murocorallia and Septocorallia are founded on the presence or 

 absence of so-called ' thecal ' pieces. This is a partial revival of 

 the classification proposed by von Heider and adopted by Ortmann, 

 it has been severely criticised by von Koch and others, and it is not 

 too much to say that it is founded on a misconception. There is 

 no essential difference between ' thecal ' and ' septal ' structures. 

 Both are formed in the same manner from the same regions of the 

 polyp. In many forms sections taken low down in the corallum 

 show an alternation of septal and apparently thecal pieces. Higher 

 up it is found that calcareous lamellae project inwards from the 

 supposed thecal pieces, so that the last named appear as septa. The 

 same coral appears to have an ' eutheca ' in one part, a ' pseudotheca ' 

 in another part, is therefore a Murocorallian in one region, a Septo- 

 corallian in another. This fact has been repeatedly emphasised by 

 von Koch, and a clear and convincing discussion of the question is to 



