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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
columella, or a spongy columella may be very considerably developed. Endotheca is well developed 
and quite vesicular; the dissepiments are thin. 
It is evident that this one specimen, except in the matter of form, comprises all of the four above- 
discussed species. Whether a coral head is spheroidally rounded above or somewhat elongated in one 
direction is so much a matter of pure chance, depending upon the object to which it is attached, etc., 
that no one would think of separating species on that basis. 
It seems to me that Mxandrina superficial is of Milne- Ed wards & Haime, judging from the specimen 
1 saw in Paris, may belong here, but according to their description it is a synonym of M. clivosa. To 
what species it should be referred depends upon whether the surface of the corallum is thrown into 
lobes. In my notes on the Paris specimens I have placed it in the synonymy of Mxandrina strigosa, 
and have added “septa to cm. 19, all of the same size; width of valleys, 4 to 6 mm., depth only about 
2 mm.; columella, lamellar, interrupted, surrounded by very little vesicular tissue.” However, 
superficial) e may belong under clivosa of Ellis & Solander. 
The Leptoria fragilis of Duchassaing & Michelotti is the same as Mxandrina heterogyra, and falls 
into the synonymy of P. viridis. I am not positive as to what should be done with their Leptoria 
hieroglyphica, but probably it also should be placed in the synonymy of viridis. 
The Mxandrina labyrinthiformis and Mxandrina strigosa figured by Pourtales in the Florida Reefs 
Corals 1 are the same species. The labyrinthiformis has lower collines and the septa are more broadly 
rounded over the summits of the collines, while in strigosa the septa have a tendency to be almost 
angular where they cross the wall. The paliform lobes are represented as being fully developed in 
strigosa. The amount of variation of each of these features in a single corallum has already been 
pointed out. 
A few notes on the variation of some other specimens should be added. There is a specimen, 
the labyrinthiformis type, from Eastern Dry Rocks, Florida (collected by Palmer), that I thought 
could be kept separate from the other specimens, because the septal dentations are not saw-toothed 
(“en scie”), but often are rather long spines, or they may even be forked. We possess from Ber- 
muda a single specimen, in which both types of dentation exist, though in this the teeth are usually 
longer than in the majority of specimens, but it is not abnormal and the passage to the usual condition 
is perfect. 
It seems scarcely necessary to expand these notes of characters and variation further. Quelch 
has made extremely interesting remarks in his report on the Challenger reef corals (pp. 91-94). He 
recognizes Mxandrina labyrinthica, Mxandrina sinuosissima, and Mxandrina . strigosa, with the remark that 
sinuosissima may be only “a very thick and hard triangular walled variety” of strigosa. I go further 
than he and place the labyrinthica or labyrinthiformis in the same species, but three usually good 
varieties may be recognized, in the line of Quelch’ s separation into three species. 
This species can be defined only in terms of its variation. One character seems absolutely inva- 
riable, i. e., the form of the upper surface; it is uniformly rounded and never thrown into gibbosities. 
There is one large, fine specimen in the collection from Mayaguez, Porto Rico. Tt, is a uniformly 
rounded head, with no gibbosities, 35 cm. high and 52.5 cm. in diameter. The base is flatfish. The 
valleys are very long and usually sinuous, width from 5 to 8 mm., usually 6 mm. wide, depth 4 mm. 
or less. The collines may be rounded or subacute, wall between series is thick or thin along the 
summit, compact and usually stout. The number of septa to the centimeter is variable; a common 
scheme is about 1 4 large septa, with a varying number of smaller ones. In one instance there are 14 
large and 13 small, in another 14 large and 7 small, in another 17 large and no small. The septal 
dentations are strong, acute saw-toothed, and fairly regular. The paliform lobes are well developed. 
Columella fairly well developed, spongy, sometimes showing a lamellar element along the middle. 
1 Mem. Mus. Comp. Zool., vol. vii, No. 1, 1880. 
