GARDINER—MADREPORARIAN CORALS. 261 
Lithactinia. Milne-Edwards and Haime suggested that two species of Polyphyllia, 
P. pileiformis and P. galeriformis, very inadequately described by Dana *, really belonged 
to the genus Lithactinia, and later Quelch f identified four ‘ Challenger’ specimens as 
belonging to these two species, two to each. Of these the larger specimen of L. pileiformis 
is formed from a fragment of some larger corallum, which has commenced to grow out 
in every direction. This original fragment has indications of a central row of calicles. 
In one part of the whole corallum the septa belong to only one series, but in others have 
the same arrangement as in P. talpina. The second specimen is also growing out from 
a fragment, which shows part of a central row of calicles. This fragment has the same 
elongated, looping arrangement of the smaller septa round the pieces of the broken up 
larger septa as shown in Milne-Edwards and Haime’s figure of Polyphyllia pelvis. 
Both specimens thus have septal arrangements so similar to P. talpina that they must 
be regarded as belonging to the same genus. They, however, are very thin and delicate, 
and have other characters which separate them specifically. 
The specimens of the other ‘Challenger’ species, Z. galeriformis, show no real 
differences from those of the last, either in their costz, septa, or spinulation. Their 
undersides have indications from sand about them that they were picked up off a sandy 
bottom. This is quite sufficient to account for the differences in their costal characters 
from those of L. péleiformis, though these divergences are not greater than those of any 
half-dozen specimens of Fungia fungites picked up at random on any coral-reef. Both 
specimens have regenerated from broken fragments, the old piece in the larger appearing 
almost like one of the ends of a P. talpina, with which species the septal arrangements 
likewise agree. The smaller form alone of the four specimens shows no indication of a 
central furrow, regeneration having taken place from side calicles only. This regeneration 
in all specimens is quite independent of the radiation of the original fragment, fresh lines 
forming abruptly even at right angles to its direction. 
It must be then, I think, quite clear that Quelch’s specimens of Lithactinia really 
belong to some species of Polyphyliia, with which they agree also in the surface 
characters of their coste and septa. At the same time their relationship to Lithactinia 
nove-hibernié is undeniable. All three species must, in my opinion, be referred to 
Polyphyllia. 
The species of Cryptabacia, Polyphyllia, and Lithactinia must now be referred to a 
single genus, of which ¢a/pina (syn. pelvis) is the type, this same species being also the 
type on which Polyphyllia and Cryptabucia were founded. According to the laws 
of priority, Polyphyllia or Lithactinia should be the name of the genus, both being 
proposed in the same year}. In the absence of precise information as to the chronology 
and also as to the characters of the latter genus, it will be convenient to restore the 
genus Polyphyllia (Quoy and Gaimard), Dana. 
Lastly, Zoopilus, Dana, according to Vaughan §, “is scarcely more than a Halomitra 
* Zooph. p. 317, pl. xxi. figs. 3, 4 (1846). Lesson’s description of a species of Lithactinia was apparently 
unknown to Dana. 
+ ‘Challenger’ Reports, p. 142 (1886). 
+ Lesson’s work is dated 1831, but it was not apparently published until 1833 
§ Proc. U.S. Nat. Mus. xxviii. p. 880 (1905). 
