Study of Madrppovarian Corals. 171 



While not here primarily concerned with the work as a literary- 

 production, it is impossible to avoid expressing a regret at its really 

 great and needless length. Further, one notes a looseness in the 

 use of certain words which, is harmless unless the word itself 

 happens to be important. The authoress's use of the word 

 "homologous" is so ambiguous, indeed, that some of her sentences, 

 even when their real meaning as gathered from the context is 

 correct, do her injustice. For instance, on p. 158, "a single 

 branch of the Mussa corallum is the homologue of the whole massive 

 corallum of a Heliastrcea or Goniastrcea" ; and again, "a single tooth 

 of a IJussa septum is the exact homologue of the complete septum 

 of Galaxea." 



Coming now to the scientific portion of the work, in a short 

 review it is only possible to refer to the leading points. Von 

 Koch, Fowler, and Bourne had already established that the coral 

 skeleton was secreted by the ectoderm ; Miss Ogilvie finds that this 

 takes place by the actual calcification and death of successive layers 

 of ectoderm cells, the supply of these cells being maintained by cell 

 division. Miss Ogilvie does not seem quite to appreciate the im- 

 portance of this latter statement ; she merely asserts it. The death 

 of the ectodermal cells and their utilization as hard units in the 

 formation of epidermal structures is well known in the animal 

 kingdom, but as to the method of replenishing these cells much 

 has still to be learned ; hence, while not doubting Miss Ogilvie's 

 observations, zoologists will be generally disappointed that she 

 dismisses this very important part of the observation without any 

 figure, and in less than a single line. 



The septa being secreted in folds of the ectoderm are composed of 

 two apposed layers of skeletal matter. These septa not only rise in 

 height, but mutually support one another in different ways : for 

 instance, local thickenings of adjoining septa, or granules from their 

 faces, may meet and fuse. Here is Miss Ogilvie's second solid 

 contribution, continuing and amplifying the work of Pratz. She 

 finds that these septa with their outgrowths are not only built up of 

 discarded calcified cells, but that these cells are grouped into units 

 of structure of different orders and degrees of importance. Before 

 discussing these structural elements and her application of them, 

 I must call attention in passing to a doubtful use of words. In 

 describing these septa and the outgrowths from their lateral surfaces, 

 Miss Ogilvie continually speaks of invaginations of the wall being 

 filled up by skeletal matter. On p. 125 we find : " Is the ectoderm 

 smooth, so is the skeletal lamella. Is the ectoderm wrinkled, pitted, 

 grooved," etc. See also pp. 137, 138. On p. 180: "New 

 invaginations .... give rise to new centres of calcification." 

 And again, '-'invagination" is sometimes most confusingly used where 

 the object referred to is the skeletal part contained in it. Is not this 

 a begging of the question and thus misleading? Are septa and their 

 surface-granules and synapticula3 formed by active infoldings of the 

 body- wall which are secondarily filled up by coral substance? 

 There seems to me some confusion of thought in the use of this 



