rrototheca of the Mad rf-por aria. 3 



of tl)e same problem as that which here interests us. I shall 

 confine myself solely to showing- how some of the chief 

 transformations of the skeleton can be linked into series and 

 how, in a few cases, the causes which led to those transforma- 

 tions are apparent. We are justified in hoping that the 

 conclusions obtained from the cojitinued studies of the soft 

 parts on the one hand and of the skeleton on the other will 

 ultimately coincide. 



I wish to make it specially clear that only a few of the 

 lines of modification can be dealt with, but those few, being 

 some of the earliest, are, I believe, the most fundamental and 

 important for the elucidation of all the later transformations 

 of the coral skeleton. To deal with the whole of these latter 

 would be to write a complete systematic account of the stony 

 corals. This is the aim of the great catalogue now being 

 prepared and published by order of the Trustees of the 

 British Museum, and must be a work of years *. 



The researches of the writer in reference to this work so 

 far hardly entitle him to speak with confidence on any other 

 of the larger divisions than the Perforata ; no other has as 

 yet been systematically dealt with by him, at least in the 

 thorough manner required for a British Museum Catalogue. 

 It would not, however, have been possible to discover the 

 morphology of tliese highly specialized Perforate forms 

 without a study of and constant reference backwards to earlier 

 and simpler types. In this way certain lines along which the 

 stony corals have travelled, viz., those leading from the most 

 primitive to the most specialized, have been growing clearer. 



* The last attempt to deal ^ith the whole of the coral system in the 

 ' Hist. Nat. des Coralliaires ' of Milne-Edwards aud Haime, completed 

 iu 18G0 by Milue-Edwaids aloue, was founded on comparatively small 

 collections aud written at a time when the relations between the skeleton 

 and the polyps were not understood. The excellence of the results which 

 were nevertheless obtained is, on the one hand, a tribute to the genius of 

 the great French naturalists, and, on the other, a witness to the compa- 

 rative unimportance of the polyp, morphologically, as compared with the 

 skeleton. 



The new catalogue projected by the authorities of the British Museum, 

 and rendered necessary by the immense increase in the collections due 

 especially to the sending out of scieutitic expeditions, was started in 1876, 

 but was interrupted by the death of Dr. Briiggemann, who was engaged 

 for the purpose. After fourteen years Mr. George Brook undertook the 

 work, but again death intervened soon after the tirst volume was published 

 in 1893. Two years were again lost, when the present writer was 

 appointed to continue the work. There are now four volumes published, 

 aud the fifth is rapidly approaching completion. Each volume is practi- 

 cally a monograph of one, or at the most two, genera, and, like the earlier 

 attempt of Milne-Edw^rds and Haime, it now describes the fossil as weJl 

 as the recent forms. 



1* 



