FLORIDA REEFS. 49 
home nearer the surface ; such a home being made ready for them by 
their predecessors, they now establish themselves on the top of the coral 
wall and continue its growth for a certain time. These are the Ma^andrinas 
(Plate IX.), or the so-called Brain-Corals, and the Pontes (Plates XII. and 
XVI.). The Mfeandrinas differ from the Astrteans by their less compact 
and definite pits. In the Astra3ans the place occupied by the animal in 
the community is marked by a little star-shaped spot, in the centre of 
which all the partition-walls meet. But in the Ma^andrinas, although all 
the partitions converge toward the centi-al opening, as in the Astra^ans, 
these central openings elongate, run into each other, and form waving 
furrows all over the surfoce, instead of the small round pits so character- 
istic of the Astrseans. The Porites resemble the Astrseans, but the pits 
are smaller, with fewer partitions and fewer tentacles, and their whole 
substance is more porous. 
But these also have their bounds within the sea : they in their turn 
reach the limit beyond which they are forbidden by the laws of their 
nature to pass, and there they also pause. But the coral wall continues 
its steadv progress; for here the lighter kinds set in, — the Madrepores 
(Plates XVII., XVIII., and XIX.), the Millepores (Plate XX.), and a great 
variety of Sea-Fans (Plate XXL), and Corallines (Plate XXII.), and the 
reef is crowned at last with a many-colored shrubbery of low feathery 
growth. These are all branching in form, and many of them are simple 
calciferous plants, though most of them are true animals, resembling, 
however, delicate Algje more than any marine animals ; but, on examination 
of the latter, one finds them to be covered with myriads of minute dots, 
each representing one of the little beings out of which the whole is 
built, while nothing of the kind is seen in Algas. 
I would add hei'e one word on the true nature of the Millepores, long 
misunderstood by naturalists. While pursuing my investigations on the 
coral reefs of Florida, one of these Millepores revealed itself to me in its 
true character of Acaleph. It must be remembered that they belong to 
the hydroid group of Acalephs, of which our common jelly-fishes do not 
give a correct idea. It is by their soft parts alone, — those parts which 
are seen only when these animals are alive and fully open, — that their 
Acalephian character can be perceived, and this accounts for their 
being so long accepted as Polyps, when studied in the dry coral stock. 
Nothing could exceed my astonishment when for the first time I saw 
