OF NEW SOUTH WALES. 297 



spite of the immense work that has been done by Messrs. Dana, 

 Milne Edwards and Haime, and the careful elaboration that has 

 followed from such industrious observers as Professors Duncan, 

 Verrill, Messrs. Grosse and Wall, there is a very great deal of 

 confusion and obscurity attached to the subject. It will be seen 

 in this essay that the classification is founded on the presence or 

 absence of pali, columella, costas, epitheca, endotheca, synapticulas ; 

 the structure of the wall and character of the endotheca, the 

 edges of the septa and the mode of division or spreading. Now 

 the nature and offices of the various organs first enumerated, 

 are not understood, and the organs themselves are not defined in 

 a satisfactory manner. Pali may be regarded by some as lobed 

 septa, or vice versa ; epitheca is a mere external secretion to 

 protect against injury, an organ often present and absent in the 

 same species ; the septa united in the centre may be called a 

 columella, or it may then be stated to be absent. Endotheca and 

 synapticulas may graduate into one another, and synapticulse may 

 result from the union of granules on opposite septa, and thus two 

 such widely sundered groups as Turbinolida3 and Eongidae, be 

 united.* The costaa also are subject to great variation, and in a 

 species of Gylicia to which reference will be hereafter made, one 

 of the many calices had a series of buttress-like costaa thrown out 

 on the outside of the epitheca. All these things show that a 

 sound classification of the Madreporaria, is yet to be found. The 

 work of Messrs. Edwards and Haime is a wonderful monument 

 to their genius and industry ; but like the beautiful and apparently 

 simple system of Linnasus, is too artificial to be practically useful as 

 the knowledge of the subject increases. 



The greatest difficulty with me has been the pali. Professor 

 Duncan (in the Proc. Zool. Soc. fur 1876, p. 435), says: — "There 

 is some difficulty in classifying certain species on account of the 

 very arbitrary manner in which certain modifications of the 

 internal parts of the septa are decided to be pali. Pali, in the 

 strict and proper sense, should arise from the internal base of the 



' This has actually occurred ; one species of Heterocyathus^being removed to Stephanoseris 

 because of the granules of the opposite septa uniting. 



