262 PERCY SLADEN TRUST EXPEDITION. 
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with very few calices, and these are near the central corallite.’ While laying great 
stress on this observation, the specimen examined by Vaughan being probably the type 
of the genus, I would point out that Dana states that Zoopilus has “the polyp mouths 
between the large ridges of the surface,” but “the animals are still unknown.” It 
evidently has its subsidiary calicles over the smaller septa of the corallum, whereas the 
rest of the colonial Fungiidze have them over the larger septa. In Zoopilus, in fact, 
only the smaller septa are broken by calicular centres as compared with the larger septa 
in other genera; but there are three to six smaller septa between neighbouring larger, 
whereas in other genera the septa form two series of different sizes which alternate with 
one another. These characters, if correctly stated, are sufficient to constitute a separate 
genus, but the description is not sufficient to give any indication of its affinities. It has 
apparently granular septal teeth and spines, which would separate it from Halomitra, 
The median depression in the figure is said by Dana to be due to an accident, but it is 
useless to speculate further on the matter. In any case I doubt the generic distinction 
of Zoopilus. 
It will now be evident that I am able to recognize only four or five genera of 
colonial Fungidee :— 
I. Halomitra. 
II. Déderleinia, gen. n. 
Ill. Herpolitha. 
IV. Polyphyllia (syn. Cryptabacia, Lithactinia). 
? V. Zoopilus. 
Of these genera Herpolitha and Polyphyllia typically have elongated coralla, but the 
two genera are widely different in the nature of their septal sides and edges and their 
coste. Judging by these characters, Herpolitha finds its affinities in the Scutaria-group 
of Fungia, specimens of the type species of which often exhibit somewhat similar splitting 
up in some of their septa, while those of Polyphyllia must rather be sought for in the 
Echinata-group. 
Of the other genera, Halomitra in its surface characters and in young specimens shows 
distinct affinities to the Fungites-group of Fungia; and Déderleinia, in its extraordinarily 
granular septa and costee with their spines and teeth, as well as in other characters, has 
relationship to the Repanda-group. Zoopilus, if a good genus, must have had a different 
origin to any of the above. Finally, the affinities of Podabacia, if it has had its ancestry 
in Fungia, must be sought in the Repanda-group. 
Lastly, we may perhaps briefly refer to the relationships of the Groups of Fungia to 
one another. Of these groups all except Cycloseris and Diaseris (joined by Déderlein as 
the Patella-group) contain quite recent species, probably all Pleistocene. The Cycloseris- 
group is found fossil from the Cretaceous to the present day, and the Diaseris-group 
from the Miocene. Fungia patella perhaps contains more characteristics of the primitive 
forms than any other living species, and in these respects it must be regarded as the 
central form from which all the rest originated. First the Diaseris-group separated in 
the late Eocene or early Miocene, and then subsequently, at the commencement of the 
Quaternary period, a great breaking out in many directions suddenly formed a series of 
