1897] SOME NEW BOOKS 125 



to the modifications introduced by Martin Duncan and Quelch will 

 scarcely recognise the classification set forth in a very ingenious 

 diagram on page 331 of this work. Corals are divided into two 

 sections, Zaphrentoidea or Madreporaria Haplophracta and Cyatho- 

 phylloidea or Madreporaria Pollaplophracta. The former section is 

 divided into two sub-sections, the Coenenchymata, including the 

 families Poritidae, Madreporidae, Pocilloporidae, Oculinidae ; and the 

 Murocorallia, including the Zaphrentidae, Turbinolidae, Amphias- 

 traeidae and Stylinidae, the two last named being new families, or 

 nearly so. Ev/phyllia is taken as the living type of the Amphias- 

 traeidae, Galaxea of the Stylinidae. The section Pollaplophracta is 

 divided into two sub-sections ; the Septocorallia, including the families 

 Cyathophyllidae, Astraeidae and Fungidae, and the Spinocorallia, 

 including the family Eupsammidae. It will be seen that the old 

 groups of Aporosa and Perforata as well as the Kugosa disappear 

 altogether ; that corals which were known as perforate are placed 

 alongside of aporose corals and vice versa ; thus the Eupsammidae 

 are ranked near the Astraeidae, the Pocilloporidae near the Madre- 

 poridae. 



These sweeping changes are based upon a microscopic examina- 

 tion of the coralla of many recent and extinct forms. Make a section 

 through a coral skeleton and you will recognise in the middle of each 

 septum, or other component, a dark line or centre. With thin sections 

 and high powers the dark line resolves itself into a series of dark 

 spots, from which the crystalline elements of the corallum radiate 

 outwards in diverse ways. A close comparative study of these features 

 has convinced Miss Ogilvie — or we should rather say now, Mrs 

 Gordon — that they afford a new and natural basis for classification, 

 one which is applicable to the study of both extinct and recent corals, 

 because the feature in question is usually well preserved in fossil 

 remains. A further convenience is the fact that the microscopical 

 structure of the corallum may often, if not always, be inferred from 

 its superficial characters, e.g. granules, striae, and serrations of septa. 

 To give details of the septal characters is here impossible ; the struc- 

 ture is intricate and demands much space for explanation. It need 

 only be said that anybody, having read this part of the work, may 

 easily verify the truth of the statements made. Points which have 

 hitherto escaped notice are here brought forward for the first time, 

 and the new observations are invested with an importance which, if 

 not always acceptable, is invariably interesting and suggestive. 



Miss Ogilvie not only describes the microscopic character of the 

 corallum ; she also accounts for it by seeking to prove that the 

 ultimate elements of the coral skeleton are minute scales, each com- 

 posed of a bunch of minute crystalline fibres, and that each such scale 

 is in fact a calcified cell or calicoblast, which is bodily converted into 

 the calcareous tissue of the skeleton. In making this assertion Miss 

 Ogilvie treads on contentious ground. She adopts and expands a 

 view originally put forw T ard by von Heider, but not generally accepted, 

 because it appeared to_be negatived both by examination of fresh adult 

 coralla and by the embryological researches of von Koch. The latter 

 author, whose statements are worthy of the utmost credit, states most 

 positively that in the development of Astroides calycalaris, the first 



