REPORT ON CORALS—HYDROCORALLIN #, a 
sending this chapter (on the Madreporaria Tabulata) to the press, we learn that Professor 
Agassiz has studied the mode of the organisation of the soft parts of the Milleporide, 
and has proved that these Zoophytes are not corals, but Hydroid Acalephs very nearly 
related to the Hydractiniz. Professor Dana shares the opinion of Professor Agassiz ; 
and Agassiz believes that the Favositidee, as well as all other species of which the septa 
are not continued vertically, ought to be considered strangers to the class of corals. But 
the facts on which he grounds his opinion are not as yet sufficiently ascertained for us 
to be able to form a critical opinion of their value; and, until more ample information 
is received, we shall continue to rank the polyps in question according to the method 
adopted in our former works.” 
Professor L. Agassiz, in his Contributions to the Natural History of the United 
States,' figured the animals of Millepora. He placed Millepora, Heliopora, Seriato- 
pora, Pocillopora, and the whole of the Tabulate and Rugose Corals with the Hydroid 
Acalephz. The principal distinction between these sections and true polyps relied on 
by Agassiz, was as follows? :—‘ The pits into which the animals (7.e., of the Milleporidze 
and their supposed allies) retreat have a horizontal floor extending from wall to wall, 
and these floors are built successively one above another as the animal rises, the 
radiating portion never extending vertically through successive floors. Not so with 
the Actinoid Polyps, in which the radiating partitions extend from the top to the 
bottom of the pit, while the horizontal floors, if they exist, extend only from one 
radiating partition to another.” Agassiz hoped that deep-sea dredgings would produce 
additional evidence concerning the affinities of Millepora, and genera connecting more 
closely the Rugosa and Tabulata with one another, and with the Acalephe, in the 
shape of branching Heliopores and the like. (A letter concerning deep-sea dredgings 
addressed to Professor Benjamin Pierce, Superintendent of the United States’ Coast 
Survey, by Louis Agassiz, Cambridge, Mass., Dec. 1871.) He had “not the remotest 
doubt that the Tabulata were genuine Hydroids.”® From the time when Agassiz’s 
observations on Millepora were published until the completion of the present paper, 
no one made any examination of the structure of the soft parts of any of the members 
of the Tabulata, with the exception of Professor Verrill who examined a Pocillopora, 
and found it to be a true Zoantharian polyp with twelve septa and twelve tentacles 
(Ann. and Mag. Nat. Hist., 1872, vol. ix., 4th series, p. 355, from Silliman’s American 
Journal, 1872, vol. iii. pp. 187-194, On the Affinities of Palzeozoic Tabulate Corals with 
Existing Species). Quoy and Gaimard had, however, long before described the twelve 
short tentacles of Pocillopora damicornis. 
Professor Verrill, in the paper above quoted, as he had done before, combated the 
conclusions of Professor Agassiz that the whole of the Tabulata belonged to the Hydroid 
1 Louis Agassiz’s Contribution to the Natural History of the United States of America, vol. iii. pl. xv. 
2 Thid., p. 61. 3 Thid., p. 121. 
