384 BULLETIN OF THE 



acquired of the Fungian affinities of Siderastraea leaves no doubt in my 

 mind that a large number of corals, among the representatives of the 

 Oolithic series generally referred to the family of Astraeans, are genuine 

 Fungians ; thus showing a preponderance of the Fungian type at a 

 period anterior to that in which the Astrrcans became more numerous. 

 That the genuine Madreporians are of still later date in geological 

 history has long been known. I would state also that from an examina- 

 tion of the soft parts of several representatives of the family of Eupsam- 

 midcB, I have satisfied myself that they are not allied to the true Mad- 

 repores, as Milne Edwards and Haime supposed, but belong in the 

 neighborhood of the Turbinolians. If we now remember that the Acale- 

 phian affinities of the Tabulata are unquestionable, and that, with them, 

 the Rugosa must be removed from the class of Polyps and referred to 

 that of the Acalephs; and if we further take into consideration the fact 

 that Palceodiscus belongs to the type of Rugosa, and not to the family of 

 Fungians, it becomes evident that in their order of succession from the 

 Mesozoic era, in which they make their first appearance, the great types 

 of the class of Polyps have succeeded one another in the following order : 

 first Turbinolians, next Fungians, next Astraans, and last Madrepores ; 

 in exactly the sequence in which these types stand to one another, as 

 far as their structural gradation is concerned, and in exactly the same 

 order in which, during their growth, these corals pass from one stage to 

 another. 



If we now turn our attention to the distribution of these animals in 

 the ocean at different depths, it is equally unquestionable that the lowest 

 types — Turbinolians and Eupsamrnida) — range in the greatest depths, 

 and form there the principal feature of the coral population. It is 

 equally apparent, from the facts ascertained by the dredgings of M. 

 Pourtales, that the various types of Astrreans, including Stylaster, Ocu- 

 lina, and Parasmilia, appear next, the Stylasterians and Oculinians as 

 the lowest ranging deepest, and that Astraea proper, Manicina, Mean- 

 drina, and Colpophylia, with Porites, are already types of shallower 

 waters, while the Madrepores are, of all the genuine corals, those 

 which have the most limited bathymetric range. I have not yet suf- 

 ficient data upon the relative standing of the different types of Ilal- 

 cyonaria to extend this comparison to that order of Polyps. The re- 

 sults enumerated above are, however, already sufficient to show that 

 in the relations animals exhibit among themselves and to the elements 



